Nondestructive testing of ceramic components: Cooperative research and development agreement completion report

In a joint Cooperative Research and Development Agreement (CRADA) between Martin Marietta Energy Systems (MMES) and an industrial partner, Y-12 has been evaluating nondestructive evaluation (NDE) techniques to identify the quality of high strength aluminum oxide tubes used in laser applications. In Phase I, several NDE techniques were developed to inspect the tubes. In Phase II a correlation between detected defects, actual failure mode and strength of the tubes was developed. In Phase II the industrial partner supplied tubes manufactured under a variety of conditions and containing material defects expected from process control variations. The tubes were inspected at MMES utilizing a variety of available acoustic techniques. After inspection, ring tensile specimens were fabricated to determine the tensile strength. The data were evaluated utilizing Weibull statistics to determine the statistical impact of the defects upon strength and correlate the data with the nondestructive evaluations of the tubes and observed defect distribution

Integrin α6β4 Promotes Autocrine Epidermal Growth Factor Receptor (EGFR) Signaling to Stimulate Migration and Invasion toward Hepatocyte Growth Factor (HGF)

Integrin α6β4 is up-regulated in pancreatic adenocarcinomas where it contributes to carcinoma cell invasion by altering the transcriptome. In this study, we found that integrin α6β4 up-regulates several genes in the epidermal growth factor receptor (EGFR) pathway, including amphiregulin (AREG), epiregulin (EREG), and ectodomain cleavage protease MMP1, which is mediated by promoter demethylation and NFAT5. The correlation of these genes with integrin α6β4 was confirmed in The Cancer Genome Atlas Pancreatic Cancer Database. Based on previous observations that integrin α6β4 cooperates with c-Met in pancreatic cancers, we examined the impact of EGFR signaling on hepatocyte growth factor (HGF)-stimulated migration and invasion. We found that AREG and EREG were required for autocrine EGFR signaling, as knocking down either ligand inhibited HGF-mediated migration and invasion. We further determined that HGF induced secretion of AREG, which is dependent on integrin-growth factor signaling pathways, including MAPK, PI3K, and PKC. Moreover, matrix metalloproteinase activity and integrin α6β4 signaling were required for AREG secretion. Blocking EGFR signaling with EGFR-specific antibodies or an EGFR tyrosine kinase inhibitor hindered HGF-stimulated pancreatic carcinoma cell chemotaxis and invasive growth in three-dimensional culture. Finally, we found that EGFR was phosphorylated in response to HGF stimulation that is dependent on EGFR kinase activity; however, c-Met phosphorylation in response to HGF was unaffected by EGFR signaling. Taken together, these data illustrate that integrin α6β4 stimulates invasion by promoting autocrine EGFR signaling through transcriptional up-regulation of key EGFR family members and by facilitating HGF-stimulated EGFR ligand secretion. These signaling events, in turn, promote pancreatic carcinoma migration and invasion

Responding to a Community's Concern: A Comparison of Breast Cancer Characteristics and Initial Treatment in Three Selected North Carolina Counties

BACKGROUND A 2007 national report identified North Carolina's Edgecombe County as having among the highest breast cancer incidence and mortality rates nationally, motivating the initiation of a task force and other local efforts to address the problem. The goal of this study is to examine county breast cancer characteristics before and after the report, including whether geographic variation may mask racial disparities in this majority African American community. METHOD With guidance from community partners, breast cancer cases from 2000 to 2012 in Edgecombe, Nash, and Orange Counties (N = 2,641) were obtained from the North Carolina Central Cancer Registry. Bivariate and trend analyses of tumor and treatment characteristics were examined by county and race. RESULTS Women in Edgecombe and Nash Counties were diagnosed with more advanced stage, higher grade tumors. African Americans in Edgecombe and Nash Counties were diagnosed with advanced disease more often than African Americans in Orange County. Average time-to-treatment was well within guideline recommendations. Incidence and mortality rates appear to have declined, with variation in measures of racial differences over time. LIMITATIONS Changes in coding standards across the observation period required reliance on coarse measures that may partially mute useful findings. CONCLUSIONS Racial disparities remain a concern in North Carolina; however, they appear to be less profound than in the 2007 national report. The portentous statistics in the report represent an all-time high, after which some, but not all, measures reflect positive change amidst ongoing local efforts to improve breast cancer knowledge and care

Rotational bands in neutron-rich 169,171,172Er

The neutron-rich 169,171,172Er nuclei were populated by few-neutron transfer reactions between 170Er and 238U at a near barrier energy. The spectroscopy of these Er isotopes was studied using prompt γ rays correlated with delayed transitions or events involving at least three prompt transitions. The ground-state band of 172Er was populated up to spin 22+ at an excitation energy of 5528 keV. Rotational bands built on the 1/2-[521], 5/2-[512], and 7/2 +[633] neutron configurations in 169,171Er were extended to substantially higher spins than previously known. The signature splitting observed in these rotational bands is addressed within the framework of the particle-rotor model in terms of triaxiality and Coriolis attenuation. The signature inversion observed in the 5/2-[512] band is well reproduced by including the triaxial degree of freedom in the calculation. Attenuating the Coriolis interaction in the calculation is found to be necessary to reproduce the signature splitting observed in the 7/2+[633] band. A similar Coriolis attenuation also is needed to account for the signature splitting as well as the B(M1)/B(E2) ratios in the 7/2+[633] ground-state band in the neighboring N=99 isotones, 167Er and 169Yb

Kπ = 4- isomers and their rotational bands in 168,170Er

The half-life of the known I,Kπ=4-,4- state in 170Er has been measured to be 42.8±1.7 ns. The rotational band built on this isomer was excited inelastically up to spin 18- by a 238U beam at Elab=1358 MeV. A similar band in 168Er was extended to spin 15-. The wave function of the isomeric state in 170Er has been determined from the measured |gK-gR| values, which were deduced from the intensity ratios of the ΔI=1 to δI=2 transitions within the band. The dominant component consists of a two-quasiproton configuration involving the Nilsson orbits 7/2-[523] and l/2+[411]. In contrast, the two-quasineutron configuration involving the 7/2+[633] and 1/2 -[521] Nilsson orbits constitutes the major component for the wave function of the Kπ=4- isomer in 168Er

Complex band interactions in 170Er

Inelastic excitation of 170Er by a 238U beam, studied at near-barrier energies, has led to the observation of unusual features in rotational bands built on low-lying vibrations. The population of the high-spin members of the Kπ=0+, β-vibrational band is enhanced due to mixing with the Kπ=2+, γ-vibrational band at spin 4+. Strong mixing of the Kπ=0+ band with a rotationally aligned 2 qp band results in this band losing its β-vibrational character and in a rapid gain in spin alignment leading to a crossing with the ground-state band between spins 2O+ and 22+. The low-lying Kπ=3+ band also is populated. It subsequently decays to both the γ-vibrational and the ground-state bands. The occurrence of appreciable K-forbidden E2 transitions from the Kπ=3+ to the ground-state band is attributed to mixing with the Kπ=2+ band, caused by the interaction between the quadrupole γ-vibrational and the hexadecapole vibrational motions

Microscopic Structure of High-Spin Vibrational Excitations in Superdeformed 190,192,194Hg

Microscopic RPA calculations based on the cranked shell model are performed to investigate the quadrupole and octupole correlations for excited superdeformed bands in 190Hg, 192Hg, and 194Hg. The K=2 octupole vibrations are predicted to be the lowest excitation modes at zero rotational frequency. At finite frequency, however, the interplay between rotation and vibrations produces different effects depending on neutron number: The lowest octupole phonon is rotationally aligned in 190Hg, is crossed by the aligned two-quasiparticle bands in 192Hg, and retains the K=2 octupole vibrational character up to the highest frequency in 194Hg. The gamma vibrations are predicted to be higher in energy and less collective than the octupole vibrations. From a comparison with the experimental dynamic moments of inertia, a new interpretation of the observed excited bands invoking the K=2 octupole vibrations is proposed, which suggests those octupole vibrations may be prevalent in SD Hg nuclei.Comment: 22 pages, REVTeX, 12 postscript figures are available on reques

Impact of triaxiality on the rotational structure of neutron-rich rhenium isotopes

A number of 3-quasiparticle isomers have been found and characterised in the odd-mass, neutron-rich, 187Re, 189Re and 191Re nuclei, the latter being four neutrons beyond stability. The decay of the isomers populates states in the rotational bands built upon the 9/2-[514] Nilsson orbital. These bands exhibit a degree of signature splitting that increases with neutron number. This splitting taken together with measurements of the M1/E2 mixing ratios and with the changes observed in the energy of the gamma-vibrational band coupled to the 9/2-[514] state, suggests an increase in triaxiality, with γ values of 5°, 18° and 25° deduced in the framework of a particle-rotor model

Dynamic moment of inertia of the 192Hg superdeformed band at high rotational frequencies

The superdeformed band in 192Hg has been extended to higher transition energies from a new analysis of a large set of double and triple coincidence data. Contrary to the results of cranked shell model calculations including monopole pairing, the dynamic moment of inertia I(2) is found to continue to increase with rotational frequency