THE REACTION OF C60F20 WITH ANTHRACENE: FORMATION OF AN OXIDISED-ANTHRACENE 1 : 1 COMPLEX

The reaction of C₆₀F₂₀ (“Saturnene”) with anthracene yields a white 1 : 1 cycloadduct (1) in which two oxygen atoms have inserted into the anthracene framework due to fullerene-catalysed oxidation; the ¹⁹F NMR spectrum of the product shows evidence of through-cage homoconjugation.     

Comorbid panic disorder and major depression: implications for cognitive-behavioral therapy

The Fourier transform infrared spectrum of H3SiI has been recorded in the nu1/nu4 region from 2075 to 2315 cm-1 at an optical resolution of 2.3 x 10(-3) cm-1. The nu1/nu4 fundamental bands and the (nu1 + nu3) - nu3/(nu4 + nu3) - nu3 hot bands have been rotationally investigated. Numerous local perturbations have been observed in the nu1 and nu4 bands and in the hot bands. Without the lines involved in perturbations, more than 2900 transitions of the nu1/nu4 bands were used to determine the band origins and the vibration-rotation parameters of the nu1 = 1 and nuv4 = 1 states. A least-squares fit of 766 apparently unperturbed transitions of the hot bands gave the parameters of the nu1 = nu3 = 1 and nu4 = nu3 = 1 states. The l(2, 2) resonance in nu4 and the A1-E Coriolis coupling between nu1 and nu4 have been investigated. Most of the local perturbations have been studied individually using a simple model by which the main perturber for each resonance was identified. Copyright 1998 Academic Press.     

Diabetes complications and risk factors in an Australian population. How well are they managed?

BACKGROUND: This study aimed to explore the relationship between complications and risk factors in the type 2 diabetes population, and to assess the level of assistance people with diabetes receive in controlling their risk factors. METHODS: Participants were recruited from representative population surveys of South Australians aged over 18 years. Participants were asked a series of questions about their risk factors and the advice and assistance they received from their general practitioner (GP) in modifying their risk factors. Additionally, participants were clinically tested for a number of macro and microvascular complications. RESULTS: South Australians with type 2 diabetes have a high prevalence of risk factors, with the majority being overweight or obese, doing no vigorous exercise and having high blood pressure. They also have a high prevalence of complications, with 53% having at least one macrovascular complication and 66% having at least one microvascular complication. Additionally, participants reported high levels of GP advice and assistance on the risk factors where pharmacological controls were available, but low levels of assistance where non-pharmacological interventions were needed to control the risk factor. CONCLUSIONS: The prevalence of diabetes risk factors and complications among South Australians with type 2 diabetes is a cause for concern, as is the lack of assistance offered by GPs to modify risk factors. Multi-disciplinary approaches to the control of risk factors and patient self-management and education are critical to the progression and success of diabetes care.     

A new high performance phase shifter using BaxSr1-xTiO3 thin films

In this paper, a new device topology has been proposed to implement parallel plate capacitors using Ba_xSr_1-xTiO₃ (BST) thin films. The device layout utilizes a single parallel capacitor and minimizes conductor losses in the base electrode. The new design simplifies the monolithic process and overcomes the problems associated with electrode patterning. An X-band 180° phase shifter has been implemented using the new device design. The circuit provided 240° phase shift with an insertion loss of only 3 dB at 10 GHz at room temperature. We have shown a figure of merit 93°/dB at 6.3 GHz and 87°/dB at 8.5 GHz. To our knowledge, these are the best figure of merit results reported in the literature for distributed phase shifters implemented using BST films at room temperature     

Subcellular site of expression and route of vaccination influence pulmonary eosinophilia following respiratory syncytial virus challenge in BALB/c mice sensitized to the attachment G protein

The attachment glycoprotein (G) of respiratory syncytial virus (RSV) is synthesized as two mature forms: a membrane-anchored form and a smaller secreted form. Mutant cDNAs were constructed that encoded one or the other form of the protein and were expressed in recombinant vaccinia viruses (rVV). Mice were immunized with rVV by dermal scarification or i.p. injection to determine the contribution of the membrane-anchored and secreted forms of the G protein on the augmentation of pulmonary pathology seen following RSV challenge. Mice scarified with rVV expressing the membrane-anchored G protein had a markedly reduced pulmonary eosinophilic response following RSV challenge compared with mice scarified with rVV expressing either wild-type or secreted G protein. The induction of pulmonary eosinophilia in rVV-primed mice was also dependent upon the route of vaccination. An eosinophilic response was not observed in any groups of mice immunized i.p. with rVV expressing any of the different forms of the G protein. The difference in pulmonary pathology observed between dermal scarification or i.p. vaccinated mice was not reflected in a difference in cytokine production by splenocytes from vaccinated and challenged mice restimulated with RSV in vitro. Both groups produced significant levels of IL-4 and IL-5. These data suggest that the local APCs and lymphoid environment, together with the form of the G protein, influence pulmonary pathology following RSV challenge.     

Accretion rate of cosmic spherules measured at the South Pole

Micrometeorites are terrestrially collected, extraterrestrial particles smaller than about 1 mm, which account for most of the mass being accreted to the Earth. Compared with meteorites, micrometeorites more completely represent the Earth-crossing meteoroid complex and should include fragments of asteroids, comets, Mars and our Moon, as well as pre-solar and interstellar grains. Previous measurements of the flux of micrometeoroids that survive to the Earth's surface have large uncertainties owing to the destruction of particles by weathering, inefficiencies in magnetic collection or separation techniques, low particle counts, poor age constraint or highly variable concentrating processes. Here we describe an attempt to circumvent these problems through the collection of thousands of well preserved and dated micrometeorites from the bottom of the South Pole water well, which supplies drinking water for the Scott-Amundsen station. Using this collection, we have determined precise estimates of the flux and mass distribution for 50-700-microm cosmic spherules (melted micrometeorites). Allowing for the expected abundance of unmelted micrometeorites in the samples, our results indicate that about 90% of the incoming mass of submillimetre particles evaporates during atmospheric entry. Our data indicate the loss of glass-rich and small stony spherules from deep-sea deposits, and they provide constraints for models describing the survival probability of micrometeoroids.     

The delineation of ionic pathways in organic coatings using a molecular probe technique

The mode with which ions enter organic coatings when subjected to corrosive environments remains unresolved. Local electrochemical methods have provided insight into the local nature of the underfilm degradation process. But these local electrochemical methods have not provided conclusive evidence as to whether the transport of water and ions occurs through discrete heterogeneities within the organic film, or whether these species enter as a uniform front and then elicit localized corrosion dictated by heterogeneities on the substrate surface (e.g., intermetallic particles). The mode of ion entry through thin (10 μm) epoxy coatings was investigated using a chloride-specific chromophore in conjunction with fluorescence microscopy. Epoxy coatings were spin cast onto glass slides and exposed to NaCl solutions at ambient and low (pH=2.5) pH for 1, 3, and 7 days. An additional variable included the age of the coating component materials as assessed from the date of manufacture. Following exposure to chloride solutions, the films were exposed to a chloride-specific chromophore, 6-methoxy-N-ethylquinolinium iodide (MEQ). Fluorescence microscopy indicated that chloride ions were clustered in discrete sites on the surface of the coatings. The number of defect sites appeared qualitatively to increase with NaCl exposure time, but not to increase at low pH. This proof of concept experiment provides a possible new avenue for the characterization and quantification of coating degradation.     

High-yield flip-chip bonding and packaging of low-threshold VCSEL arrays on sapphire substrates

Oxide-confined top-emitting 850 nm and bottom-emitting 980 nm vertical-cavity surface-emitting laser (VCSEL) 8/spl times/8 arrays were designed and fabricated for applications of optical interconnects. The arrays were flip-chip bonded onto sapphire substrates that contain complimentary metal-oxide-semiconductor (CMOS) driver and fan-out circuitries. The off-sited bonding contacts and minimized bonding force produced very high yield of the hybridization process without causing damage to the VCSEL mesas. The hybridized devices were further mounted either on printed circuit board (PCB) or in 68-pin pin-grid-array (PGA) packages. The transparent sapphire substrate allowed optical outputs from the top-emitting VCSEL arrays to transmit directly through without additional substrate removal procedure. Lasing thresholds below 250 /spl mu/A for 850 nm VCSELs and 800 /spl mu/A for 980 nm VCSEL were found at room temperature. The oxide confinement apertures of VCSELs were measured to be around 6 /spl mu/m in diameter. High-speed data transmission demonstrated a bandwidth of up to 1 Gbits/s per channel for these hybridized VCSEL transmitters.     

Effects of postmortem freezing on tensile failure properties of rabbit extensor digitorum longus muscle tendon complex

The tensile failures of extensor digitorum longus muscle tendon units from 16 male New Zealand White rabbits were studied in the fresh state (less than 30 minutes after death) and in the frozen/thawed state (frozen at -80 degrees C for 28 days and then warmed to 38 degrees C). Frozen/thawed extensor digitorum longus muscle tendon units had significantly lower values for load to failure (p < 0.01), energy absorbed to failure (p < 0.01), and strain at failure (p < 0.01), and they tended to fail at a different anatomic location (p < 0.01) (broadly at the fascia-muscle interface as compared with horizontally at the musculotendinous junction) than fresh units. The results of this study suggest that freezing muscle tendon units significantly alters their tensile failure characteristics.     

Effect of rendering procedures on the scrapie agent

A pool of scrapie-infected sheep brains was used to spike mixtures of porcine bone and intestine. These were processed in pilot-scale facsimiles of 12 rendering procedures that were in use within the European Union in 1991, and three that were not. Meat and bone meal, and tallow, were produced from the rendered tissues. Suspensions of all the meat and bone meal samples, and two of the tallow samples were assayed in mice for scrapie infectivity. Neither of the tallow samples had any detectable infectivity but the meat and bone meal samples were positive, except for those produced by processes involving exposure to hyperbaric steam. In addition, greaves were produced from the scrapie-spiked raw materials by an atypical low-temperature process and subjected to solvent extraction with hot heptane. The treated greaves were then exposed to steam to drive off residual solvent. Although the starting titre of infectivity in these greaves was low, there appeared to be no reduction in infectivity as a result of the treatments with hot heptane and steam. However, there was no detectable infectivity in the meat and bone meal prepared from the greaves produced by the atypical low-temperature process after it had been exposed to hyperbaric steam.