Prediction of axillary lymph node involvement of women with invasive breast carcinoma: a multivariate analysis

BACKGROUND: The increasing use of systemic therapy for women with lymph node negative breast carcinoma and earlier stage of disease at mammographic detection raises questions regarding the need for routine axillary lymph node dissection. Predictive modeling for lymph node involvement may be one way to reduce the need for axillary lymph node dissection and its morbidity. METHODS: A multivariate analysis of 12 factors predictive of axillary lymph node involvement was conducted in a population-based cohort of 4312 women with invasive breast carcinoma diagnosed between January 1, 1993 and December 31, 1996. RESULTS: Clinical palpability, lymphatic or vascular invasion, lesion size, margin status, histology, and patient age were independent predictors of axillary lymph node involvement. The model correctly identified lymph node status in 76.6% of cases. Model accuracy and fit were equally high when applied to randomly selected halves of the study subjects. Approximately 32.0% of the patients in the study sample (1363/4312) were identified as having an extremely high (91%; n = 1102) or low (10%; n = 261) risk of lymph node involvement. In a second analysis, a clinically useable, three-variable model identified a very low risk group of patients (n = 147) with a 4.8% risk of lymph node metastasis and a high risk group of patients (n = 1008) with a 74.2% risk of lymph node metastasis. Greater than 90% of subjects in the high risk group received adjuvant systemic therapy even if they were lymph node negative pathologically. CONCLUSIONS: A clinically useable, three-variable model employing tumor and lymph node palpability, size, and lymphatic or vascular invasion can identify women with invasive breast carcinoma in whom axillary lymph node dissection is very unlikely to alter recommendations regarding adjuvant systemic therapy.     

High brightness single-mode ridge laser utilizing buried heterostructure defined by quantum-well intermixing

The authors demonstrate a novel high brightness single-lateral mode ridge laser using quantum well intermixing to form a buried heterostructure. Increased discrimination between the fundamental and higher order modes can be achieved using the buried heterostructure to reduce the width of the gain section, enhancing fundamental mode operation. This allows the ridge width to be increased while maintaining fundamental mode operation, hence reducing the optical intensity at the facet and increasing the optical power before mirror degradation. Standard and novel buried heterostructure ridge lasers of 5-/spl mu/m width are compared; far-field beam profiles clearly show improved modal stability for the novel structure.     

Melt elasticity of low density polyethylene

The stress vs strain and strain recovery characteristics of a series of low density polyethylenes of various molecular size and molecular size distributions have been studied in the melt state. The results show that the high molecular size portion of the molecular size distribution dominates the stress vs strain behavior. The high molecular size component causes a large increase in the stress overshoot and steady state stress. The high molecular size component also has a strong influence on the magnitude of recoverable strain, The strain recovery characteristics are dependent on the amount of strain applied. For large strains (above the yield point) the strain recovers slowly to a large extent (Type I). For applied strains below the yield point the strain recovery is rapid and finished in a short period of time (Type II).     

Synthesis and Characterization of Furazan Energetics ADAAF and DOATF

The synthesis and structural characterization of bis[4-aminofurazanyl-3-azoxy]azofurazan (ADAAF) and 3,4:7,8:11,12:15,16-tetrafurazano-1,2,5,6,9,10,13,14-octaazacyclohexadeca-1,3,5,7,9,11,13,15-octaene-1,10-dioxide (DOATF) are described. Explosive sensitivity properties of both materials were determined. The heat of formation of ADAAF was measured to be 300 kcal/mol and the detonation velocity and pressure of ADAAF were measured to be 7.88 km/s and 299 kbar, respectively, at 94% theoretical maximum density. We also investigated the burning rate characteristics of ADAAF.     

Materials Design and Discovery with High-Throughput Density Functional Theory: The Open Quantum Materials Database (OQMD)

High-throughput density functional theory (HT DFT) is fast becoming a powerful tool for accelerating materials design and discovery by the amassing tens and even hundreds of thousands of DFT calculations in large databases. Complex materials problems can be approached much more efficiently and broadly through the sheer quantity of structures and chemistries available in such databases. Our HT DFT database, the Open Quantum Materials Database (OQMD), contains over 200,000 DFT calculated crystal structures and will be freely available for public use at http://oqmd.org. In this review, we describe the OQMD and its use in five materials problems, spanning a wide range of applications and materials types: (I) Li-air battery combination catalyst/electrodes, (II) Li-ion battery anodes, (III) Li-ion battery cathode coatings reactive with HF, (IV) Mg-alloy long-period stacking ordered (LPSO) strengthening precipitates, and (V) training a machine learning model to predict new stable ternary compounds.     

Direct detection of hydrocarbon displacement in a model porous soil with magnetic resonance imaging

The direct detection of hydrocarbon fluid and the discrimination of water through carbon-13 magnetic resonance imaging (MRI) would be a significant advance in many scientific fields including food, petrogeological, and environmental sciences. Carbon-13 MRI is a noninvasive analytical technique that has great potential for direct detection of hydrocarbons. However, the low natural abundance of carbon-13, low gyromagnetic ratio, and generically short transverse signal lifetimes in realistic porous media all conspire to hinder carbon-13 MRI. A multiple echo pure phase encode MRI technique introduced in this paper helps to overcome these limitations. As a pure phase encode technique, it is immune to artifacts arising from inhomogeneous B0 fields. It is also, by its nature, more quantitative than most MRI methods. Viscous hydrocarbon flow through a sand bed, a simple realistic porous medium, was used as our test system. Flow in this model system was driven by capillary suction. The detection limit, spatially resolved, was determined to be 26 mg.