The interpretation of impedance measurements on oxide-coated aluminium part 2. The effect of flaws in As-formed films

The interpretation of a.c. impedance data, corrected for solution and double layer losses, is considered for air-formed and anodic alumina films. The effect of flaws on the impedance characteristics could be considerable at the flaw densities observed, and in certain circumstances could predominate over the prevailing structural losses in the bulk film material. A distinction is made between “residual” flaws, associated with regions of impurity segregation in the surface and present in all films, and “mechanical” flaws, associated with relatively gross structural defects in the metal and particularly predominant in air-formed films.     

Defensive sesquiterpenoids from a dipterocarp (Dipterocarpus kerrii)

Four sesquiterpenoids (2, 4, 7, and9) have been isolated and characterized from the termiticidal fraction ofDipterocarpus kerrii resin. The major constituent of this resin is -gurjunene (1).Presented at the Third Annual Meeting of the International Society of Chemical Ecology, June 21–24, 1986, University of California, Berkeley.     

Identifying the task variables that influence perceived object assembly complexity

There is a general lack of understanding as to what issues affect assembly task performance when using diagrammatic instructions because few of the task variables contributing to assembly complexity have been identified. Using a task analysis of a range of self-assembly products, seven task variables hypothesized to predict assembly complexity were identified and studied in the instruction comprehension phase of assembly. Experiment 1 took nine real world assembly instructions and described each in terms of the seven task variables. Seventy-two participants gave a subjective rating of assembly difficulty for each assembly, showing a clear relationship between the task variables and perceived assembly difficulty. As real world assemblies provide little control a second experiment used an orthogonal design to systematically vary the values of each of the assembly task variables in 16 abstract assemblies. Forty-two participants compared the 16 assembly instructions to a final assembly. There was a clear relationship between the task variables and the time taken to view the instructions. Further, it was found that it is possible to predict the complexity of assembly tasks based upon the levels of the task variables identified. The task variables identified are a significant step towards identifying the factors that influence assembly complexity, together with providing progress towards a tool for predicting assembly complexity.     

Spectroelectrochemical sensing based on attenuated total internal reflectance stripping voltammetry. 2. Determination of mercury and lead

Detection of lead and mercury by attenuated total internal reflectance spectroscopy coupled to stripping voltammetry is demonstrated. Changes in attenuation of light passing through an indium tin oxide optically transparent electrode (ITO-OTE) accompany the electrodeposition and stripping of lead and mercury on the electrode surface. The change in absorbance during stripping of electrodeposited metal constitutes the analytical response that enables detection over a range of 2.5 x 10(-7)-5 x 10(-5) and 5 x 10(-8)-5 x 10(-5) M for mercury and lead, respectively. The spectroelectrochemical responses of mercury and lead on the ITO surface are characterized and optimized with respect to solution conditions, the potential excitation signals used for deposition and stripping, and wavelength for detection. The deposited metals were examined by environmental scanning electron miscroscopy, and the electrodeposition pattern of lead and mercury was found to influence the optical response.     

Lysosomes and essential fatty acid deficiency

The hydrolytic activity usually associated with lysosomes increased in the homogenates and subcellular fractions of rat liver as a result of essential fatty acid (EFA) deficiency. The proportion of the total (tissue homogenate) activity found in each subcellular fraction, however, was unchanged by EFA deficiency. Lysosomes isolated from normal and EFA-deficient rat livers differed significantly in their stability to thermal and osmotic variations. This suggested that lysosomal membranes, like other membranes, were altered by EFA deficiency. In spite of increased tissue-bound hydrolytic activity and altered lysosomal membranes, hydrolytic activity of the serum was not markedly changed in EFA deficiency. These minor changes in hydrolytic activity and in lysosomal membrane stability seemed insufficient to explain the general lesions of EFA deficiency. Published with the approval of the Director of The Wisconsin Agricultural Experiment Station.     

Program evaluation: resource for decision making

Formal program evaluation is an important resource for health care decision making. It is necessary in situations where traditional organizational evaluative capabilities an no longer meet the requirements of the job at hand.     

The acute effects of amitriptyline, iprindole and trazodone on blood pressure and heart rate in rats

The cardiovascular effects of the tricyclic anti-depressant amitriptyline, a monoamine uptake inhibitor, and iprindole and trazodone, two novel anti-depressants of unknown mechanism, were monitored in urethane anesthetized rats following intravenous (IV) or intracerebroventricular (IVT) injection. Amitriptyline (2 mg IV or 0.25 mg IVT) produced hypotension that might reflect an action of norepinephrine on the anterior hypothalamus. Iprindole (2 mg IV) produced hypertension and (0.25 mg IVT) tachycardia that is consistent with a partial beta-agonist mechanism. Trazodone (1 mg IV or 0.25 mg IVT) produced hypotension and bradycardia that is consistent with the activation of noradrenergic neurons in the anterior hypothalamus perhaps as a result of trazodone acting on presynaptic alpha 2 receptors or on presynaptic serotonin receptors to increase the release of norepinephrine. All three of these anti-depressants have the potential to precipitate cardiovascular complications, particularly in patients with pre-existing cardiovascular abnormalities.     

Spin-wave phenomena in liquid3He systems

The magnetic effects predicted by Leggett and Rice for Fermi liquids in the collisionless regime have been verified. Spin-echo measurements are reported which demonstrate the existence of spin waves and undamped spin currents in liquid³He and dilute³He-⁴He solutions. The experimental results are compared with the theoretical expressions of Leggett and Rice, and values of the Fermi liquid interaction parameter $$\lambda = \left[ {1/(1 + F_0^a )} \right] - \left\{ {1/[1 + (F_1^a /3)]} \right\}$$ are derived for three samples: liquid³He atP=0 and 27 atm, and a 6.4%³He-⁴He solution. In addition, some techniques for direct observation of individual spin-wave modes are explored and the results reported.