Tunable Cerenkov lasers

The concept of a tunable Cerenkov laser is introduced and expressions for the operating wavelength and stimulated emission rate are developed. Emphasis is on the development of criteria which must be met if tunable far-infrared device operation is to be achieved.     

A Prototype Portable Electronic Speaking Aid for the Nonvocal Handicapped

A new type of speaking aid for the vocally handicapped is described. The portable device has as key elements a speech synthesizer, a hand-worn touch-sensitive command device, and appropriate interfacing built around a microprocessor. The user, a nonvocal person with reasonable control of at least one hand, uses an augmented variation of finger spelling to command the synthesizer to output phonemes. A prototype is described and early testing is discussed.     

Microbeam RBS on flat panel displays

We have demonstrated the utility of microbeam-Rutherford BackScattering (μ-RBS) in spatially resolved studies of operational plasma effects on the interior surfaces of plasma flat panel displays manufactured by Photonics Imaging. The experiments were performed at the Sandia Nuclear microprobe using a 2.8 MeV He beam with an average beam spot size of less than 8 μm. The interior surface of the top panes of the flat panels is composed of approximately 800 nm of MgO on top of a 2000 nm thick PbO layer. μ-RBS of sample panels operated under varying conditions measured changes in the surface MgO film thickness due to plasma erosion and redeposition as accurately as ± 1.5 nm. The high accuracy in the MgO thickness measurement was achieved by inferring the MgO thickness from the shift of the Pb front edge in the RBS spectrum. An estimate for the thickness accuracy as a function of the acquired statistics is presented. The surface of the flat panels' bottom panes is also comprised of MgO on top of PbO. However, troughs 100 μm wide by 10 μm deep were partially filled with phosphor and cover the entire width of the surface. This leaves only 100 μm long sections of MgO within the trough exposed. Using μ-RBS, we were able to analyze the surface composition of these regions.     

Self-in-relation theory and the role of the clinical nurse specialist. Part II: Application to advanced nursing roles in a professional practice model

CONCEPTS AND ASSUMPTIONS of self-in-relation theory of women's development, as proposed by feminist scholars at the Stone Center in Wellesley, Massachusetts, are applied in this article. This theory was used as a framework to guide staff development and mentorship roles of advanced practice nurses. How the theory served to direct these roles and assisted in development of a professional practice model is discussed. Exemplars from the authors' practices and professional practice outcomes after 2 years of theory implementation are presented.     

Neurite outgrowth stimulated by L1 requires calcium influx into neurons but is not associated with changes in steady state levels of calcium in growth cones

L1, NCAM and N-cadherin are cell adhesion molecules (CAMs), present on neuronal growth cones, which promote cell-contact dependent axonal growth by activating a second messenger pathway in neurons that requires calcium influx through L- and N-type calcium channels. In the present study we show that two of these CAMs, (L1 and N-cadherin) can stimulate neurite regeneration from axotomised adult dorsal root ganglion (DRG) neurons cultured in vitro and that this response can be fully inhibited by agents that block or negate the effect of calcium influx into the neurons. However although the response required calcium influx into neurons, it was not associated with an increase in the steady state levels of calcium in neuronal growth cones. These results suggest that small localised changes, or increases in the rate of calcium cycling, in growth cones and/or filopodia, are more important for regulating axonal growth than changes in the steady-state level of calcium.     

Lipopeptide phytotoxins produced by Pseudomonas syringae pv. syringae: comparison of the biosurfactant and ion channel-forming activities of syringopeptin and syringomycin

The maturational status of Adelta and C-fibers in the fetal rat spinal cord was examined using formalin-induced c-fos expression as a marker for neuronal activities. Awake 19-, 20-, and 21-day fetuses (FD) were injected ex utero with 5 microl of 10% formalin either into the ventral aspect of the forepaw or the hindpaw. FD 19 fetuses showed little response to the injection, but with increasing age, the fetuses exhibited more specific behaviors following injury of the paw. By FD 21, fetuses treated with formalin injection showed body curls and twitches, mouth opening, face wiping, and withdrawal of the injected paw. The anatomical data paralleled that of behavior; FD 19 animals expressed a small number of Fos labeled nuclei following the formalin injection that was not statistically different from control animals. The formalin-induced increase in Fos staining was first observed at FD 20 with a large increase in the number of Fos labeled cell occurring between FD 20 and 21. By FD 21, the pattern of Fos stained nuclei resembled that found in neonatal rats. There was constitutive bilateral staining in all untreated, saline and formalin injected fetuses that is unique to prenatal animals. Formalin treated fetuses showed constitutive level of staining in addition to the increase in the c-fos expression caused by formalin. We have thus demonstrated that, as indexed both by behavioral response and by Fos immunoreactivity, rat fetuses are capable of transmitting and responding to noxious input before birth.     

Binodal and spinodal curves: a simulation for various high polymer mixtures

Flory's equation-of-state theory has been used to predict the lower critical solution temperature behaviour of polymer—polymer mixtures. The spinodal phase boundary of numbers of high molecular weight polymer mixtures have been previously simulated using this theory. In this paper a procedure for simultaneous predictions of the binodal and the spinodal curves by equating the chemical potential of each component in the mixture is presented. The method is tested for five different mixtures. The effects of the binary and pure component state parameters on the simulated curves are discussed and the simulated phase diagrams are compared with the experimental cloud point curves. It is found that in most cases the results are more consistent with the cloud point curve being closer to the spinodal curve than the binodal.     

Characterization of PAX‐21 Insensitive Munition Detonation Residues

Insensitive high explosives are being used in military munitions to counteract unintended detonations during storage and transportation. These formulations contain compounds such as 2,4‐dinitroanisole (DNAN) and 3‐nitro‐1,2,4‐triazol‐5‐one (NTO), which are less sensitive to shock and heat than conventional explosives. We conducted a series of four tests on snow‐covered ice utilizing 60‐mm mortar cartridges filled with 358 g of PAX‐21, a mixture of RDX, DNAN, and ammonium perchlorate. Rounds were detonated high‐ and low‐order using a fuze simulator to initiate detonation. Blow‐in‐place (BIP) operations were conducted on fuzed rounds using an external donor charge or a shaped‐charge initiator. Results indicate that 0.001 % of the original mass of RDX and DNAN were deposited during high‐order detonations, but up to 28 % of the perchlorate remained. For the donor block BIPs, 1 % of the RDX and DNAN remained. Residues masses for these operations were significantly higher than for conventional munitions. Low‐order detonations deposited 10–15 % of their original explosive filler in friable chunks up to 5.2 g in mass. Shaped‐charge BIPs scattered 15 % of the filler and produced chunks up to 15 g. Ammonium perchlorate residue masses were extremely high because of the presence of large AP crystals, up to 400 μm in the recovered particles.