Increased Dispersion of Supported Gold during Methanol Carbonylation Conditions

The active site in supported gold catalysts for the carbonylation of methanol has been identified as dimers/trimers of gold which are formed from large gold particles >10 nm in diameter. Methyl iodide was found to be critical for this dispersion process and to maintain the catalyst in the active form. This study also shows that it may be possible to redisperse gold catalysts, in general, after reaction.

Capital substitutability and weak sustainability revisited: The conditions for capital substitution in the presence of risk

The capital approach is frequently used to model sustainability. A development is deemed to be sustainable when capital is not reduced. There are different definitions of sustainability, based on whether or not they allow that different forms of capital may be substituted for each other. A development that allows for the substitution of different forms of capital is called weakly sustainable. This article shows that in a risky world and a risk-averse society even under the assumptions of weak sustainability the circumstances under which different forms of capital may be substituted are limited. This is due to the risk-reducing effect of diversification. Using Modern Portfolio Theory this article shows under which conditions substitution of different forms of capital increases risk for future generations.

General local and rectilinear vibrational coordinates consistent with Eckart's conditions

We present a general method to construct a set of local rectilinear vibrational coordinates for a nonlinear molecule whose reference structure does not necessarily correspond to a stationary point of the potential-energy surface. We show both analytically and with a numerical example that the vibrational coordinates satisfy Eckart's conditions. In addition, we find that the Watson Hamiltonian provides a fairly robust description even of highly excited vibrational states of triatomic molecules, except for a few states of large amplitude motion sampling the singular region of the Hamiltonian. These states can be identified through slow convergence.

Effect of temperature and mixing conditions on quality and consistency of poly(methyl methacrylate) bone cement

The mixing of poly(methyl methacrylate) (PMMA) bone cement has been studied to develop methods for preparing a consistently high quality cement. A novel droplet test experimental procedure was developed that characterised the wetting characteristics involved in bone cement mixing. Using this technique it was established that increased wetting occurred by mixing bone cement at a lower temperature (-28 degreesC) than normal mixing at room temperature.

Soft x-ray free electron laser microfocus for exploring matter under extreme conditions

We have focused a beam (BL3) of FLASH (Free-electron LASer in Hamburg: lambda = 13.5 nm, pulse length 15 fs, pulse energy 10-40 mu J, 5Hz) using a fine polished off-axis parabola having a focal length of 270 mm and coated with a Mo/Si multilayer with an initial reflectivity of 67% at 13.5 nm. The OAP was mounted and aligned with a picomotor controlled six-axis gimbal. Beam imprints on poly(methyl methacrylate) -PMMA were used to measure focus and the focused beam was used to create isochoric heating of various slab targets. Results show the focal spot has a diameter of

Reliability of blood pressure determination with the Finapres with altered physiological states or pharmacodynamic conditions

The blood pressure waveform is modified on distal propagation by phenomena such as dispersion, reflection and the state of the arterial compliance. The consequent effects are amplification and narrowing of the wave, with an increased systolic, reduced diastolic and essentially unaltered mean blood pressure. The Finapres measures the peripheral pressure using the volume clamp principle; it has not been validated under altered physiological conditions and during pharmacodynamic interventions. We studied simultaneous Finapres and brachial blood pressures (using a conventional oscillometric sphygmomanometer—Vitalmap) in ten normal volunteers at rest, and during dynamic exercise and a cold pressor test. The effects of pharmacodynamic intervention were examined following beta-adrenoceptor blockade with propranolol (160 mg) or beta-adrenoceptor modulation with the beta-adrenoceptor partial agonist celiprolol (400 mg). The Finapres systolic pressure was significantly higher than the brachial value during all three test states. The difference between the systolic pressures measured by the two devices was shown to increase significantly during the cold pressor test, but not during dynamic (supine bicycle) exercise. The Finapres diastolic pressure was significantly higher than the Vitalmap value during exercise and the cold pressor test. The differences between the two methods increased significantly over time. Beta-adrenergic blockade with propranolol or modulation with celiprolol had no significant interaction with the pressure differences between the Finapres and Vitalmap techniques. The results would support the view that the Finapres can provide blood pressure information which is robust under most circumstances. Although this pharmacodynamic intervention did not alter the relationship between the peripheral and central blood pressure, it is important to note that this dynamic relationship is sensitive to circulatory loading conditions and wave transmission characteristics; it is possible that the Finapres could be less reliable in clinical settings where potent vasoactive agents were being administered.