Assessment of oil contamination in the marine environment by pattern recognition analysis of paraffinic hydrocarbon content of mussels

Data on the paraffinic hydrocarbon content of mussels (Mytilus edulis and M. califomianus) were analyzed statistically in an attempt to assess oil contamination of several aquatic areas of the greater Puget Sound basin in the State of Washington. The mussels were collected quarterly over a period of two years from ten locations. Fundamental statistical treatment of the data did not reveal meaningful trends. Application of pattern recognition techniques to the hydrocarbon data set allowed the mussel samples to be successfully classified into groups, from areas near known sources of potential pollution or from areas remote from known pollution. Several samples however, could not be grouped consistently as either from contaminated or uncontaminated sites. In addition, the mussels from a particular area could be separated as to season of sampling. Seasonal variation in levels of individual paraffinic hydrocarbons were greater than annual changes. The n-C₁₆ hydrocarbon concentration was the most useful of the 34 features studied for establishing possible oil contamination of the areas. The n-C₁₆ hydrocarbon content was also used successfully to detect oil spills and to define uncontaminated locations in Puget Sound.     

Constituents of morphologically similar sponges : Aplysina and smenospongia species

Compounds from the marine sponge Smenospongia aurea have been isolated and characterized as 5-bromo- and 5,6-dibromo-N,N-dimethyltryptamines (1 and 2), aureol (3), and two new aplysinopsin derivatives (6-bromoaplysinopsin and 6-bromo-4'-N-demethylaplysinopsin, 4 and 5, respectively). Morphologically similar species from the Caribbean have been surveyed and found to contain either mixtures of these metabolites or bromotyrosine-derived compounds. ¹H NMR spectra of bromoindole-containing metabolites are discussed.     

Therapeutic systems and controlled drug delivery

Therapeutic systems can provide pre-programmed, unattended delivery of a drug at a rate, and for a time period, established to meet a specific therapeutic need. The system can be designed to minimize the patient's intervention and to optimize compliance with the prescribed regimen. The ocular therapeutic system described here for the control of intraocular pressure in glaucoma delivers pilocarpine at 20 or 40 μg/h for one week, and fits comfortably into the cul-de-sac of the eye. The intrauterine progesterone contraceptive system described here represents a new approach to steroidal contraception that localizes the effect of the hormone progesterone to the uterus, delivering the hormone at a rate of 65 μg/day for one year. Both of these systems are designed to deliver drug into their immediate locale, and are thus topical dosage forms. The transdermal therapeutic system described here has been designed to deliver scopolamine across intact skin and into systemic blood to achieve an antinausea effect. The pharmacokinetics of scopolamine are such that, to minimize the time required for the onset of drug action, drug should be presented at an initially high rate, i.e. as a priming dose, to attain the therapeutically effective drug level, and then at a constant rate, so as to maintain the therapeutically effective level. This system functions according to the priming dose/maintenance rate design requirement.     

Reactive scattering of Sn from Cl2 and Br2 and a lower limit on D00 (SnBr)

Laboratory (lab) angular and time-of-flight (TOF) recoil velocity spectra of SnCl product formed by crossing a thermal Sn beam with a Cl₂ nozzle beam have been measured in a molecular beam apparatus equipped with an electron bombardment ionizer—quadrupole mass filter detector unit. Product center of mass (c.m.) recoil angle and energy distributions have been fit to the data by convoluting the c.m. → lab transformation over measured beam speed distributions and the instrumental TOF resolution. The inferred distributions for the Sn + Cl₂ reaction are strikingly similar to those reported for the Li + Cl₂ reaction. In addition, SnBr product was observed from crossed beams of Sn and Br2 which establishes a lower limit for D⁰₀ (SnBr) of 131 kJ/mole.     

Resonance enhanced laser ionisation mass spectrometry of four aromatic molecules

Multiphoton ionisation and fragmentation of aniline, benzene, N,N-dimethyl and 2,4-dimethyl aniline has been studied by laser ionisation mass spectrometry under collision free conditions. All four molecules undergo efficient resonance-enhanced two-photon ionisation (R2PI) with relatively low laser intensities at λ = 266 nm producing the parent ion almost exclusively. At higher intensities, high order processes compete producing extensive fragmentation. At 266 nm, all the major fragment ions are produced by R3PI. For aniline excited at 294 nm, energetic considerations suggest R4P1 formation of fragments with differences in fragmentation between 266 and 294 nm reflecting the differing orders and energies above threshold of the competing processes. Comparison of R2P1 efficiencies in aniline and benzene shows that the cross sections for ionisation of the resonant intermediate ₁B² excited state in both molecules are approximately equal and independent of wavelength in the range 250–300 nm.     

The circular dichroism spectrum of S(+)-sec-butyl benzene

The absorption and CD spectra of S(+)-sec-butyl benzene are reported in the spectral region 195–180 nm. The CD spectrum contains two bands of opposite sign at 190.5 nm and 187 nm. The results are interpreted to confirm previous results for 1-methylindan in this spectral region. The observed bands are assigned to the state derived from the benzene E_2g state.     

Quantum ergodicity and the wigner distribution

A quantum ergodic analysis is developed based on comparison of Wigner phase-space densities of quantum eigenstates to classical densities. The technique is applied to the two-dimensional Henon-Heiles system. Analysis of quantum densities as a function of energy is found to clearly display the regular to ergodic transition.     

Synthesis of 1,1′-di-t-butylstannocene and its reaction with trifluoroborane. The crystal and molecular structure of η5-(CH3)3CC5H4Sn+BF4−

The reaction of Li(CH₃)₃CC₅H₄ with SnCl₂ in THF affords 1,1′-di-t-butylstannocene in 78% yield as an air-sensitive oil. ¹H and ¹³C NMR spectra are consistent with a pentahapto-structure. Mössbauer parameters of the stannocene and its trimethylsilyl counterpart match closely those of known stannocenes and neither compound appears to undergo oligomerization. The reaction of 1,1′-di-t-butylstannocene with BF₃ in CH₂Cl₂ affords η⁵-(CH₃)₃CC₅H₄Sn⁺ BF₄^? and other uncharacterized product(s) thought to involve tetracoordinate tin. The structure of η⁵-(CH₃)₃CC₅H₄Sn⁺ BF₄^? was determined by single crystal X-ray diffraction (orthorhombic,Pbcn, (T 25°C), a 18.423(3), b 11.723(1), c 11.044(2) Å, Z Å, m.p. 95–96°C, colorless, Mo-K_α, R = 0.043).