Pellet cladding interaction — Evaluation of lubrication by graphite

Graphite CANLUB interlayers between UO₂ pellets and Zircaloy cladding increase the tolerance of fuel pins to power ramping defects. This paper evaluates the effectiveness of graphite as a lubricant in dry, low oxygen potential environments such as exist at the UO₂ — Zircaloy interface of an operating fuel pin. Two types of laboratory tests were performed at 573 ± 5 K in moist air and also dry inert gas. In the first test series, graphite-coated Zircaloy cladding was expanded by the outward movement of a 4-segment bronze mandrel. Depleting the oxygen and water vapour reduced circumferential failure strains from about 19% to about 12%, but there remained a large margin of improvement over the 4% failure strain attained with bare Zircaloy. In the second series of laboratory tests a disc of UO₂ was clamped between Zircaloy plates, and the force required to cause it to slide was measured as a function of normal loading with and without graphite lubrication. The coefficient of friction μ for graphite lubricating a Zircaloy-UO₂ interface rose only slightly from 0.19 to 0.24 on changing the gaseous environment from laboratory air to dry deoxygenated helium. These values were low compared with μ ~ 0.9 for bare Zircaloy-UO₂ interfaces in air or inert gas. An indirect evaluation was made of whether or not graphite acts as a lubricant in-service by counting peripheral radial UO₂ cracks in metallographic cross-sections of irradiated fuel pins. The number of peripheral cracks in highly powered fuel depends on the interfacial shear stress at the pellet-clad interface, and hence on the friction coefficient. In fuel pins ramped to a linear power of 55 kW/m there were, on average, 17 peripheral UO₂ cracks in graphite lubricated CANLUB fuel compared with 30 in bare Zircaloy-clad fuel. We deduce that the ratio of friction coefficients in-service (CANLUB graphite : bare Zircaloy) had been 0.57 : 1.0. Finally, we discuss theoretical limitations of CAN-LUB coatings and their implications regarding fuel design and performance.     

An international quality assurance scheme for the quantitation of daidzein and genistein in food,urine and plasma

This quality assurance (proficiency testing) scheme was commissioned to enable the Food Standards Agency (FSA) to determine the quality of analytical results submitted by researchers measuring the concentrations of phytoestrogens in foods and biological fluids in FSA-funded research projects, and also, to demonstrate that FSA-funded laboratories are producing consistent and precise results. Non-FSA-funded laboratories from around the world were also invited to join in the scheme to increase the number participants. A secondary objective was to highlight the most successful methodologies used to analyse phytoestrogens.     

Multiple phases of expression and regulation of mouse Hoxc8 during early embryogenesis

Hox genes are expressed in dynamic patterns during embryogenesis consistent with their role in axial specifications. To study the distribution of mouse Hoxc8, a homeodomain containing protein, we raised monoclonal antibodies against the least conserved portion of Hoxc8. Using these antibodies, we have examined early and mid-gestation embryos for the distribution of the protein. At the end of gastrulation Hoxc8 is expressed in the caudal portion of the embryo. In the neural tube, an early phase when all cells express Hoxc8 is distinguished from a late phase with predominant expression in differentiating neurons. A comparison of this expression pattern with that of a reporter gene under the control of the early Hoxc8 enhancer demarcates three separate regulatory components: (1) initiation and establishment; (2) maintenance; and (3) downregulation. We propose that Hoxc8 expression during embryogenesis is established in multiple phases. Possible regulatory mechanisms involved in generating such a complex domain of Hox gene expression are discussed.     

Detection and characterization of the electron paramagnetic resonance-silent glutathionyl-5,5-dimethyl-1-pyrroline N-oxide adduct derived from redox cycling of phenoxyl radicals in model systems and HL-60 cells

Rapidly growing knowledge about the nature and behaviour of breast cancer has led to many treatment modalities. Consequently, the possibilities of individualizing the treatment of breast cancer increase. The major tool for the determination of an optimal treatment plan is the estimation of the extent of the disease: in other words, staging. As a consequence, together with the expected result of the treatment, the stage of the disease gives information on the prognosis of the patient. Current staging systems insufficiently describe the clinically important features of breast cancer with respect to management and outcome: local and regional extent, invasiveness, aggressiveness, the state of dissemination, and the effectiveness of different treatment modalities. For staging of the local and regional extent, histology plays a prominent role and should be incorporated in future staging systems. Histological workup therefore needs standardisation. Histological parameters as tumour size, grade, nodal status, and vascular invasion are also the most important prognostic factors. Many so-called biological prognostic factors are related to the invasiveness and aggressiveness (metastatic potential) of the tumour, and therefore to the prognosis of the patient. However, these factors do not necessarily predict the effectiveness of certain systemic treatments. Only if the biological foundation of a prognostic factor is completely clarified can treatment be based on this knowledge, and the factor will become a predictor for the treatment effect. Many "biological" prognostic factors do not fulfil this main criterion and are therefore not useful for clinical decision making. A clinically useful staging system covers three primary aims: (1) to guide locoregional treatment, (2) to prognosticate the chance of survival, and (3) to indicate who needs what kind of adjuvant treatment. For the conception of a new staging system the following steps should be taken: standardization of all aspects of histology, identification of regional nodal involvement, and validation of prognostic factors with respect to their predictive value to treatment outcome.     

Utilizing uncertainty factors in minimal risk levels derivation

While both 31P and 113Cd are present at locations of interest in many different macromolecular systems, heteronuclear-detected relaxation measurements on these nuclei have been restrained by limitations in either resolution or signal-to-noise ratio. We have developed heteroTOCSY-based methods to overcome both of these problems. Two-dimensional versions of these experiments were utilized to measure 31P T1 and T2 values in DNA oligonucleotides; the additional resolution offered by a second dimension allowed determination of these values for most of the 31P resonances in a DNA dodecamer. The results from the experiments indicated that there was little significant variation in T1 values for the different phosphates in the DNA dodecamer; however, the T2 values showed a clear pattern, with lower values in the interior of the sequence than at the ends of the helix. Furthermore, a significant correlation between 31P chemical shifts and T2 values was observed. One-dimensional, frequency-selective versions of these experiments were also developed for use on systems containing a smaller number of heteronuclear spins. These methods were applied to investigate the heteronuclear relaxation properties of 113Cd in 113Cd2LAC9(61), a Cys6Zn2 DNA-binding domain. Data from the experiments confirm biochemical evidence that more significant differences occur in the metal-protein interactions between the two metal-binding sites than has been previously identified for proteins containing this motif.     

"Snatching defeat from the jaws of victory: Self-esteem differences in the experience and anticipation of success": Correction to Wood et al (2005).

Reports an error in "Snatching Defeat From the Jaws of Victory: Self-Esteem Differences in the Experience and Anticipation of Success" by Joanne V. Wood, Sara A. Heimpel, Ian R. Newby-Clark and Michael Ross (Journal of Personality and Social Psychology, 2005[Nov], Vol 89[5], 764-780). There are typographical errors in Table 2 (certain values should not have been in bold face). The corrected table is provided in the erratum. (The following abstract of the original article appeared in record 2005-15658-009.) Successes--defined broadly as meeting important standards or receiving positive evaluations--are widely assumed to be enjoyed equally by people with high self-esteem (HSEs) and low self-esteem (LSEs). Three studies examined the contradictory hypothesis that HSEs react more favorably to success than do LSEs and that success brings about certain unfavorable consequences for LSEs. Undergraduate participants reacted to a laboratory-manipulated success (Studies 1 and 2) or imagined highly positive events in the future (Study 3). Self-esteem differences emerged in anxiety, thoughts about the self, and (in Study 3) thoughts about non-self-related aspects of the event. LSEs were more anxious than HSEs after succeeding, success improved HSEs' self-relevant thoughts but not LSEs', and LSEs focused more on success's negative aspects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of nickel in the high-temperature oxidation of Fe-Cr-Ni alloys in oxygen

The oxidation of several largely austenitic Fe-Cr-Ni alloys in 1 atm oxygen at 800–1200°C has been studied thermogravimetrically, metallographically, and in detail by electron probe micro analysis. Fe-Cr-Ni alloys of this type are protected by Cr₂O₃-healed scale, which thickens slower than on the corresponding binary Fe-Cr and Ni-Cr alloys, presumably because nickel and iron ions dope the Cr₂O₃ more effectively together than singly and/or because the alloy composition and ability to absorb cation vacancies are such as to produce a smaller vacancy activity gradient or level in the scale, or voids within it. The scale adhesion, as on Ni-Cr alloys, is generally good after long times, at least partly due to the convoluted alloy-oxide interface, in some cases to large intergranular Cr₂O₃-rich stringers, and possibly to the general specimen mechanical properties. Nonprotective stratified scale development is relatively unusual and often produces nickel-rich, alloy-particle-containing nodules, as on Fe-Ni alloys. Careful selection of ternary and more complex alloys with appropriate alloy interdiffusion coefficients and oxygen solubilities and diffusivities should permit development of materials with the best compromise between ease of Cr₂O₃ establishment, avoidance of breakaway, and readiness of scale healing.     

Acetophenone as an Anti-attractant for the Western Pine Beetle, <Emphasis Type="Italic">Dendroctonus Brevicomis</Emphasis> LeConte (Coleoptera: Scolytidae)

Host location and colonization by bark beetles is dependent upon the relative and absolute amounts of attractant and antiattractant compounds available. Many investigations have lead to use of antiattractants for the management of these pests and have been especially focused on verbenone. However, recent studies have identified new antiattractants for several species of bark beetles. We report results of recent investigations of the response of western pine beetle, Dendroctonus brevicomis LeConte, to two recently identified antiattractants, acetophenone, and fenchyl alcohol, with verbenone as a standard of comparison, in northern California. Release of both acetophenone and verbenone resulted in significantly lower trap catches of D. brevicomis in aggregation pheromone-baited traps, while fenchyl alcohol was inactive. Acetophenone was the only antiattractant that did not reduce numbers of the most abundant predator of D. brevicomis, Temnochila chlorodia (Mannerheim), responding to the attractant pheromone of its prey. Aggregation pheromone-baited traps with acetophenone also had the highest predator/prey ratio. Our results suggest that acetophenone may be part of the intra- and interspecific interactions among sympatric species of bark beetles and may have application in their control.