Dislocation substructure in Ta-Re-N alloys deformed at 77 K

High purity Ta, Ta-Re, and Ta-Re-N alloy single crystals were deformed in tension at 77 K, and the resulting dislocation arrangements were studied by transmission electron microscopy. Re and N have similar effects on the dislocation substructure. Alloying increases the fraction of primary screw dislocations at the expense of debris, tangling, and secondary dislocations. For a given increment in yield stress, Re causes much larger changes in the substructure than N. The substructures observed in Ta-Re-N alloys are similar to those in Ta-Re alloys, even though ternary alloys exhibit alloy softening and binary alloys exhibit alloy hardening. These observations can be explained in terms of the different intrinsic mobilities of edge and screw dislocations, the different interactions which substitutionals and interstitials have with edge and screw dislocations, and the large differences in concentration of substitutional and interstitial solutes.     

Memory monitoring by animals and humans

The authors asked whether animals and humans would use similarly an uncertain response to escape indeterminate memories. Monkeys and humans performed serial probe recognition tasks that produced differential memory difficulty across serial positions (e.g., primacy and recency effects). Participants were given an escape option that let them avoid any trials they wished and receive a hint to the trial's answer. Across species, across tasks, and even across conspecifics with sharper or duller memories, monkeys and humans used the escape option selectively when more indeterminate memory traces were probed. Their pattern of escaping always mirrored the pattern of their primary memory performance across serial positions. Signal-detection analyses confirm the similarity of the animals' and humans' performances. Optimality analyses assess their efficiency. Several aspects of monkeys' performance suggest the cognitive sophistication of their decisions to escape.     

Intraocular neoplastic cyst from mucoepidermoid carcinoma of the conjunctiva

An 89-year-old woman with recurrent conjunctival mucoepidermoid carcinoma developed intraocular inflammation and an elevated fundus lesion that simulated choroidal detachment in her affected right eye. Intraocular invasion of squamous cell carcinoma was suspected and the eye was enucleated. Pathologic examination of the enucleated eye showed intraocular invasion by conjunctival mucoepidermoid carcinoma that formed a suprauveal cyst lined with malignant epithelial cells. The patient developed an orbital recurrence 1 year later and underwent orbital exenteration. She died 2 years later from an unrelated cause. Conjunctival mucoepidermoid carcinoma can exhibit intraocular invasion and produce an intraocular neoplastic cyst.     

Effect of ignition conditions on upward flame spread on a composite material in a corner configuration

This paper focuses on the issue of fire growth on composite materials beyond the region immediately subjected to an ignition source. Suppression of this growth is one of the key issues in realizing the safe usage of composite structural materials. A vinyl ester/glass composite was tested in the form of a 90° corner configuration with an inert ceiling segment 2.44 m above the top of the fire source. The igniter was a square propane burner at the base of the corner, either 23 or 38 cm in width, with power output varied from 30 to 150 kW. Upward flame spread rate and heat release rate were measured mainly for a brominated vinyl ester resin but limited results were also obtained for a non-flame retarded vinyl ester and a similar composite coated with an intumescent paint. Rapid fire growth to the top of the sample was seen in replicate tests for the largest igniter power case; the intumescent coating successfully prevented fire growth for this case.     

Characterisation of xenobiotic-metabolising enzyme expression in human bronchial mucosa and peripheral lung tissues

We examined the effects of amiodarone (AMI) and desethylamiodarone (DAM) on whole-cell inward rectifying potassium current (IK1) in freshly isolated adult rabbit ventricular myocytes by using the whole-cell voltage-clamp technique, as an index of their effects on resting membrane resistance (Rm). Under control conditions, the current showed a strong inward rectification with a maximal inward current measured at -130 mV of -26.4 +/- 1.3 pA/pF and a maximal outward current measured at -50 mV of 3.5 +/- 0.3 pA/pF The current also exhibit a time-dependent activation, with a time constant of activation (tau(a)) that increased with depolarization. The maximal slope conductance normalized to cell capacitance was 0.509 +/- 0.019 nS/pE After exposure to both DAM (50 microM; n = 8) and AMI (50 microM; n = 7), rapid decrease in inward IK1 was observed. Block was restricted almost exclusively to the inward component. DAM caused a significant reduction of the maximal inward current (-20.0 +/- 2.0 pA/pF; p < 0.05), whereas AMI induced an even greater reduction of the same component (-14.1 +/- 1.2 pA/pF; p < 0.05 with respect to control and to DAM). The outward component of IK1 was not changed by either AMI or DAM (4.0 +/- 0.3 pA/pF and 3.4 +/- 0.4 pA/pF, respectively). AMI and DAM also decreased the maximal slope conductance significantly (0.297 +/- 0.019 nS/pF and 0.421 +/- 0.038 nS/pF, respectively). In addition, AMI but not DAM significantly increased the tau(a). However, the voltage dependence of the acceleration of tau(a) remained unchanged after both AMI and DAM exposure. These results allow us to conclude that AMI may induce a greater increase in the resting Rm than its main metabolite. This effect may counterbalance, at least in part, the conduction slowing due to its sodium channel-blocking properties.     

The effects of geometry and ignition mode on ignition times obtained using a cone calorimeter and ISO ignitability apparatus

Three timber-based materials were investigated by subjecting them to a constant uniform heat flux in the range 20–70 kW m^?2 using a Cone Calorimeter and the ISO Ignitability Apparatus. The specimens were examined in the vertical and horizontal orientations in the Cone Calorimeter using gas flame pilot, spark pilot and spontaneous methods of ignition. They were also studied using the ISO Ignitability Apparatus in the normal and inverted horizontal orientations using gas flame pilot and spontaneous methods of ignition. The results obtained are compared by specimen, orientation and mode of ignition.     

A computer-controlled data acquisition and analysis system for use in the characterization of plasma atomic emission sources

The characterization of new spectroscopic plasma sources for use in atomic emission spectroscopy often presents the need for information about the spatial emission characteristics of the source. In addition, information about the variation of the emission over time is often beneficial. It is also useful to be able to graphically see, in real-time, the effects of varying a particular experimental parameter. This paper describes a flexible data acquisition system in which an echelle spectrometer is interfaced to an IBM-PC compatible microcomputer. The FORTH-based ASYST software, which proves real-time display of acquired data, allows any point in the emission source to be imaged on the entrance slit of the spectrometer by using the cursor keys of the PC and a computer-controlled mirror. The different acquisition modes of the system are illustrated with examples of two-dimensional spatial profiles of the plasma and monitoring of plasma stability over time. In addition, an illustration of the optimization of the echelle''s aperture plate and photomultiplier tube positions in the focal plane is presented.