Au−Ni−Sn intermetallic phase relationships in eutectic Pb−Sn solder formed on Ni/Au metallization

Recent work has shown that a Au−Ni−Sn ternary compound with a nominal composition of Au_0.5Ni_0.5Sn₄ redeposits and grows at the interface between eutectic Pb−Sn solder and Ni/Au metallization during aging at 150°C. The present work verifies the existence of the Au_0.5Ni_0.5Sn₄ phase by examining the Sn-rich corner of the Au−Ni−Sn ternary phase diagram. The reconfiguration mechanism of the AuSn₄ from the bulk solder is also discussed, with detailed observations of the Au_0.5Ni_0.5Sn₄ microstructure. The results show that the Ni solubility limit in the AuSn₄ phase is approximately 12 at.% at 150°C and thus, the Au_0.5Ni_0.5Sn₄ phase is a ternary AuSn₄-based compound with high Ni solubility. Due to the slight solubility and the fast diffusion of Au in the eutectic Pb−Sn at 150°C, the AuSn₄ intermetallics in the bulk solder can reconfigure to form a Au_xNi_1−xSn₄ compound at the interface where Ni is available. The Au_xNi_1−xSn₄ compound layer consists of nanocrystals arranged in a larger grainlike morphology. It appears that the inherent lattice strain of the Au_xNi_1−xSn₄ compound and the volume change due to its formation results in a nanocrystalline microstructure.     

A chemical basis for differential allelopathic potential of sorghum hybrids on wheat

The basis for differential allelopathic potentials among sorghum (Sorghum bicolor L. Moench) hybrids was investigated by conducting quantitative and qualitative studies of their phenolic contents. Total phenolic content in sorghum plant parts varied within hybrids, among hybrids, and between growing seasons. Inhibition of wheat (Triticum aestivum L.) radicle growth was positively associated (r=0.66) with concentrations of total phenolics contained in plant parts. Extracts from culms contributed the higherst proportion of toxicity from sorghum plants, inhibiting radicle growth up to 74.7%. Concentrations of five phenolic acids,p-hydroxybenzoic (POH), vanillic (VAN), syringic (SYR),p-coumaric (PCO), and ferulic (FER), differed in all plant parts of the three sorghum hybrids. Concentrations of POH, VAN, and SYR were consistently higher than PCO and FER. PCO and FER wer absent from some plant parts, with FER being the most frequently missing. Inhibition of wheat radicle growth was found to be positively associated with the concentration of each phenolic acid. Vanillic acid was most highly associated (r=0.44) with inhition. Thus, above-ground sorghum tissues contained phenolic acids that contributed to allelopathic potential. Additionally, sorghum roots exuded POH, VAN, and SYR that may enhance the overall allelopathic potential of sorghum during growth and after harvest when residues remain on the soil surface or are incorporated prior to planting a subsquent crop.Journal article No. 12245 of the Missouri Agricultural Experiment Station. Product names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the products, and the use of names by USDA implies no approval of the products to the exclusion of others that may be suitable.     

Effects of signaling inescapable shock on subsequent escape learning: Implications for theories of coping and "learned helplessness."

The present experiments reveal that shuttle-escape performance deficits are eliminated when exteroceptive cues are paired with inescapable shock. Experiment 1 indicated that, as in instrumental control, a signal following inescapable shock eliminated later escape performance deficits. Subsequent experiments revealed that both forward and backward pairings between signals and inescapable shock attenuated performance deficits. However, the data also suggest that the impact of these temporal relations may be modulated by qualitative aspects of the cues because the effects of these relations depended upon whether an increase or decrease in illumination (Experiment 2) or a compound auditory cue (Experiment 4) was used. Preliminary evidence suggests that the ability of illumination cues to block escape learning deficits may be related to their ability to reduce contextual fear (Experiment 3). The implications of these data for conceptions of instrumental control and the role of fear in the etiology of effects of inescapable shock exposure are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Software Design of a General Purpose Data Acquisition and Control Executive

The software design of an executive which performs general purpose data acquisition, monitoring, and control is presented. The executive runs on a memory-based mini or micro-computer and communicates with a disk-based computer where data analysis and display are done. The executive design stresses reliability and versatility, and has yielded software which can provide control and monitoring for widely different hardware systems. Applications of this software on two major fusion energy experiments at Lawrence Livermore National Laboratory will be described.     

A survey of glazing system behavior in multi-story buildings during hurricane andrew

A focused survey of glazing system behavior in multi-story buildings in the direct aftermath of Hurricane Andrew was conducted. Seventeen buildings and four building complexes were examined between 26 August and 30 August, 1992. The buildings surveyed spanned a 32 km (19 mile) distance from Miami on the north to Cutler Ridge on the south. With few exceptions, glazing systems performed poorly and damage to building contents was extensive. The following specific observations were made: (1) impacts from windborne debris were a dominant cause of glass failure; (2) wall system anchorages sometimes failed; (3) prevention of ‘blow-through’ after internal pressurization significantly mitigated storm damage to building interiors; and (4) outer-lite-only failures occurred on some insulating glass units. Results of the survey underscore the vital importance of maintaining the integrity of a building envelope during a severe windstorm. Windborne debris must be considered in the design of architectural glazing systems, as must proper anchorages of glazing systems to building framing members.     

Stress and adenosine: II. Adenosine analogs mimic the effect of inescapable shock on shuttle-escape performance in rats.

Examined, in 3 experiments involving 208 male rats, the role of adenosine regulation in escape deficits produced by earlier exposure to inescapable shock in rats (learned helplessness). Adenosine analogs injected before escape testing mimicked the effect of earlier inescapable shock, with the magnitude of the deficit varying with dose and drug specificity for A? adenosine receptors. Agonist-induced and stress-induced escape deficits were eliminated by pretest treatment with the centrally acting adenosine receptor antagonist theophylline but not the peripheral antagonist 8-[p-sulfophenyl]-theophylline. Finally, preexposure to an ineffective number of inescapable shocks interacted in synergy with an ineffective pretest injection of adenosine agonist to maximize deficits in escape performance. These data implicate energy regulation and a central compensatory action by adenosine in the aspects of helplessness related to onservation–withdrawal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociation of interference with the speed and accuracy of escape produced by inescapable shock.

Benzodiazepines and naltrexone administered before inescapable shock block behavioral consequences of the inescapable shock such as poor shuttle box escape, reduced activity in reaction to shock, reduced social interaction, and so on. Anxiogenic β-carboline derivatives such as FR-7142 can produce these effects by themselves. In the present study, neither diazepam nor naltrexone had any effect on the interference with Y-maze choice escape accuracy produced by inescapable shock even though they both eliminated the reduction in Y-maze escape response speed produced by inescapable shock. Analogously, FG-1742 did not lead to a reduction in Y-maze choice escape response accuracy even though it did show escape responding. These data imply that inescapable shock interferes with escape choice learning and escape response speed by different mechanisms, the former not involving fear-anxiety processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Successful transplantation of porcine livers after warm ischemic insult in situ and cold preservation including postconditioning with gaseous oxygen

BACKGROUND: In order to reduce the shortage of viable donor livers for organ transplantation, a method has been developed that allows even predamaged livers from nonheartbeating donors to be used as transplantable organs. METHODS: Porcine livers were harvested 45 min after cardiac arrest of the nonheparinized donor, preflushed with heparinized saline solution, and subsequently rinsed with University of Wisconsin solution, to which superoxide dismutase was added as an oxygen free radical scavenger. Thereafter, the livers were persufflated with gaseous oxygen via the venous vascular system while immersed in University of Wisconsin solution at 4 degrees C for 4 to 5 hr. RESULTS: After orthotopic transplantation, all of the livers conditioned with gaseous oxygen were able to support life-sustaining function during the whole observation period of 7 days post transplantation, while no survival of the recipients could be obtained without the described treatment. CONCLUSIONS: The present study establishes a new perspective for the use of ischemically altered livers from nonheartbeating donors for organ transplantation under clinical circumstances.