Corrosion of SiC Mateials in N2–H2–CO Gaseous Environments: II, Durability and Mechanical Properties

Three SiC materials were exposed to two gas compositions in the N₂–H₂–CO system at 1200° and 1300°C, 133 Pa and 98.7 kPa for 50–1000 h. The durability was evaluated by fracturing bend bars at room temperature and C-rings at room temperature and 1300°C in argon. Fractography was used to correlate changes in strength with changes in flaw populations. In all three materials, surface pitting was the primary cause of degradation. Under some conditions it was found that flaw healing and new flaw formation occurred simultaneously. C-rings cut from tubes did not lose strength, although pitting occurred; however, machined bend bars lost strength under identical conditions. In the case of bend bars, following an initial loss of strength (∼10%–50%) after 50–150 h, there was typically no further loss observed with increased exposure time. Due to its higher P _co, degradation in an endothermic gas was generally more severe than that in a nitrogen–based gas.     

Entry of alphaherpesviruses mediated by poliovirus receptor-related protein 1 and poliovirus receptor

A human member of the immunoglobulin superfamily was shown to mediate entry of several alphaherpesviruses, including herpes simplex viruses (HSV) 1 and 2, porcine pseudorabies virus (PRV), and bovine herpesvirus 1 (BHV-1). This membrane glycoprotein is poliovirus receptor-related protein 1 (Prr1), designated here as HveC. Incubation of HSV-1 with a secreted form of HveC inhibited subsequent infection of a variety of cell lines, suggesting that HveC interacts directly with the virus. Poliovirus receptor (Pvr) itself mediated entry of PRV and BHV-1 but not of the HSV strains tested. HveC was expressed in human cells of epithelial and neuronal origin; it is the prime candidate for the coreceptor that allows both HSV-1 and HSV-2 to infect epithelial cells on mucosal surfaces and spread to cells of the nervous system.     

Mapping the in vivo distribution of herpes simplex virions

We describe a method for labeling enveloped viral particles with a radiotracer, indium-111, allowing labeled viruses to be traced in vivo by nuclear imaging. After initial optimization experiments, a labeling efficiency of 83% (incorporation yield) was achieved for herpes simplex virus (HSV), resulting in a specific activity of 30 microCi/10(9) PFU. The labeling procedure did not significantly reduce the infectivity of the labeled virus and the virus did not release any significant amounts of the radionuclide within 12 hr after labeling. Sequential imaging of animals after intravenous administration of the labeled virus showed fast accumulation in the liver and redistribution from the blood pool (immediately after injection) to liver and spleen (12-24 hr after injection). At 12 hr after injection 7% of the virus-associated (111)In had been eliminated from the body and the remaining organ distribution of the virus was as follows: spleen 2.87 +/- 0.54% ID/g; liver, 2.60 +/- 0.51% ID/g; kidney, 0.98 +/- 0.31% ID/g; lung, 0.57 +/- 0.10% ID/g; [corrected] and lower amounts in other organs. Our results indicate that the described method allows qualitative and quantitative assessment of viral biodistribution in vivo by nuclear imaging.     

Effect of context salience on heart rate orienting and habituation in preweanling and periadolescent rats.

Previous research indicates that target learning is facilitated in the presence of strong extraneous sensory cues (e.g., salient contextual cues) in infant, but not adult, rats (McKinzie & Spear, 1995). The present study assessed whether such facilitation of conditioning is due to age-related differences in the effect of a salient context on processing of the conditioned stimulus (tone in this case). Preweanling and periadolescent rats were presented with a tone in either the presence (salient context) or absence (plain context) of a potent odorant. Magnitude of the heart rate orienting response to the target stimulus and its subsequent rate of habituation served as dependent variables. The results revealed that preweanling, but not periadolescent, rats showed greater cardiac orienting to the auditory stimulus in the salient than in the plain context. The results suggest that a salient context may influence stimulus processing by increasing the perceived salience and, perhaps in terms of perceived intensity, of the target stimulus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Human herpesvirus-8 glycoprotein B interacts with Epstein-Barr virus (EBV) glycoprotein 110 but fails to complement the infectivity of EBV mutants

ortho-Phenylphenol (OPP), a fungicide and antibacterial agent with food residues, is carcinogenic to rat bladder. The present studies provide information on changes in urinary composition and urinary metabolites, urothelial cytotoxicity and regenerative hyperplasia, and DNA adducts in male F344 rats fed OPP. An initial experiment evaluated dietary doses of 0, 1,000, 4,000, and 12,500 ppm OPP fed for 13 weeks. There was no evidence of urinary calculi, microcrystalluria, or calcium phosphate-containing precipitate, but urothelial cytotoxicity and hyperplasia occurred at the highest dose only. In a second experiment, rats were fed dietary OPP levels of 0, 800, 4,000, 8,000, and 12,500 ppm. Urinary pH was > 7 in all groups. Urinary volume was increased at the 2 highest doses with consequent decreases in osmolality, creatinine, and other solutes. Total urinary OPP metabolite excretions were increased, mostly excreted as conjugates of OPP and of phenylhydroquinone. Free OPP or free metabolites accounted for less than 2% excreted in the urine without a dose response. Urothelial toxicity and hyperplasia occurred only at doses of 8,000 and 12,500 ppm. OPP-DNA adducts were not detected in the urothelium at any dose. In summary, OPP produces cytotoxicity and proliferation of the urothelium at dietary doses > or = 8,000 ppm without formation of urinary solids. The paucity of unconjugated metabolites and the lack of OPP-DNA adducts suggests that OPP is acting as a bladder carcinogen in male rats by inducing cytotoxicity and hyperplasia without it or its metabolites directly binding to DNA.     

Breast reconstruction in a male with a transverse rectus abdominis flap

The TRAM flap may be the best choice in male breast reconstruction not just because it can replace the missing skin and fat but also because it may be a source of hair-bearing skin similar to the native breast skin.     

The effects of composition and doping on the response of GeC-Siphotodiodes

The spectral responses of a series of heterojunction diodes of p-type Ge_1-yC_y on n-type Si (100) substrates were measured by Fourier transform infrared (IR) spectroscopy. Alloy layers 0.5 μm thick were grown by molecular beam epitaxy at a substrate temperature of 400°C and were doped p-type with different C concentrations. With increasing C content, the diode dark current decreased, and the optical absorption band edge shifted toward higher energy by 70 meV for 0.12 at% of C. The increase in energy was attributed to the composition dependence of the bandgap rather than to strain relaxation, because the GeC layers were nearly relaxed with the same strain. The photoresponsivity was 0.07 A/W at a wavelength of 1.55 μm, and 0.2 A/W at a wavelength of 1.3 μm. These measurements show that GeC photodetectors have good properties and reasonable response at technologically important near-IR wavelengths and can be fabricated by heteroepitaxy for compatibility with Si integrated circuits     

Behaviours that indicate memory: Levels of expression.

Presents examples of research topics that require better criteria as to whether an individual has or has not expressed memory for a particular episode. Some historical reasons as to why this question has not been answered and some contemporary reasons why it is important to answer it now are suggested. Associated implications for fundamental issues of the memory process such as its ontogeny, selectivity, and physiological determinants are discussed. The fundamental observation is that an acquired memory affects relatively subtle behaviors even when having no effect on conventional indices of retention. Examples are drawn from a variety of memory experiments, some using animals and some using humans as Ss. It is concluded that an inevitable step in the study of memory would seem to be more explicit analysis of behavioral reflections of acquired memories, perhaps in terms of different levels at which a memory may be expressed. (French abstract) (65 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eutrophication in peel inlet—II. Identification of critical uncertainties via generalized sensitivity analysis

A generalized sensitivity analysis was carried out on a phosphorous based model of cultural eutrophication processes in the Peel Inlet of Western Australia. The object of the analysis was to identify critical uncertainties in present knowledge of the system for the direction and planning of future research. The main hypothesis suggested by the results is that the nuisance alga, Cladophora aff. battersii, have access to nutrients in the interstitial water of the sediments in the Inlet and that a significant quantity of nutrient is deposited in the major area of Cladophora growth by river-borne sediment. Suggested areas for future research include investigation of mechanisms of deposition, release and remineralization of nutrients in the sediment, and of certain aspects of the physiology of Cladophora.