Modelling diffusion-controlled kinetics in equilibrium and driven alloys

Summary We introduce a very simple model for thermally activated atomic migration on a lattice, and several techniques to handle it. For thermodynamical systems, the model can be used for simulating decomposition paths taking into account relevant metallurgical features. Close to equilibrium, the simplest mean-field approximation of the model can be linearized with respect to the departure from equilibrium; one then gets a microscopic interpretation of classical phenomenological coefficients, such as mobility, interfacial transfer coefficient, rate constants for the coupled relaxation of concentration and order fields. Further away from the equilibrium, the nonlinearities can be taken into account in a consistent way. For driven alloys, i.e. alloys submitted to external forcing, forced atomic migration is added to the model and new features emerge: the model is supported by several experimental results some of which confirmed its predictions a posteriori.     

Metabolism-reproduction interactions in domestic animals

In farm animals as in human, reproduction is affected by changes in the level of energetic balance. The main factors that link metabolism and reproduction, like insulin, IGFs, glucose, FFA, leptin and NPY, act on hypothalamo-pituitary axis as well as on gonads by directly altering gametogenesis.     

Communication between patients with breast cancer and health care providers. Determinants and implications

BACKGROUND: This study evaluated the perceptions of patients with breast cancer of their medical interactions with providers. The determinants and psychological consequences of communication problems also were examined. METHODS: Ninety-seven patients with Stage I or II breast cancer completed a set of validated questionnaires before initiating postoperative therapy. Data on psychological distress were collected at baseline and 3-month follow-up, and multivariate models were fit to explain the relationship between pretreatment communication problems and subsequent psychological distress. Data on clinical variables were abstracted from medical records. RESULTS: A substantial proportion of patients (84%) reported difficulties communicating with the medical team. Communication problems were more common among patients who were less optimistic about their disease and had less assertive coping styles. Patient-reported communication problems were associated with increased anxiety, depression anger, and confusion at the 3-month follow-up. The association between communication problems and mood disturbance remained significant, although small, after adjusting for baseline mood disturbance, demographic, clinical, and coping style variables. CONCLUSION: Interventions that enhance communication between patients with breast cancer and their providers may improve patients' psychological adjustment to treatment. Conversely, interventions that lower distress and modify coping style may enhance communication.     

Evaluation of NR-LU-10 with the Neoprobe gamma detector in a mouse model

1. The effects of diethyl maleate (DEM) on the cytotoxicity of phenyl-hydroquinone (PHQ) and other hydroquinones were studied in freshly isolated rat hepatocytes. 2. Addition of PHQ (0.5 or 0.75 mM) to hepatocytes resulted in dose-dependent cell death accompanied by the abrupt depletion of both GSH and protein thiols and the accumulation of phenyl-benzoquinone (PBQ). 3. Pretreatment with DEM (1.25 mM), which causes an abrupt depletion of cellular GSH in hepatocytes, delayed the onset of PHQ-induced cytotoxicity. The delay correlated with inhibition of PBQ formation. 4. Although the pH of the cell suspension was increased slightly (mean pH 0.18) by incubation under carbogen flow, the addition of DEM to the cell suspension inhibited both the increase in pH and the formation of PBQ from PHQ. 5. In hepatocyte suspensions without DEM, PHQ cytotoxicity was dependent on pH, and toxicity was associated with oxidation of PHQ and accumulation of PBQ. 6. Among other hydroquinones (0.5 mM), tert-butyl-hydroquinone-induced cytotoxicity was decreased by DEM (1.25 mM), but DEM did not affect the cytotoxicity of 2,5-di(tert-butyl)-1,4-benzohydroquinone. 7. PHQ-induced cytotoxicity correlated with the accumulation of PBQ in the cell, and the inhibition of PHQ-induced cytotoxicity by DEM correlated with pH-dependent changes in PBQ formation.     

Autoregressive modelling in vector spaces: An application to narrow-bandwidth spectral estimation

A generalisation of the Burg algorithm to vector spaces is described. This can be used to subsample time series that have narrow frequency bandwidth, thereby reducing the computation time and the complexity of the autoregressive model required. The technique is preferable to conventional subsampling.     

Transient characteristics of small salient-pole alternators

The use of small alternators, other than for standby purposes, is increasing and this has focused attention on the reliability and utility of the parameters normally quoted for such machines. Test procedures are described and methods used for parameter estimation discussed, with particular emphasis on the difficulties presented by small brushless machines     

Ammoxidation of methylaromatics over vanadium phosphate catalysts II. Catalyst formation, active sites and reaction mechanism

The interactions of VOHPO₄· 0.5H₂O and (VO)₂P₂O₇ with the ammoxidation feed and the single components such as ammonia, oxygen, water and component mixtures were studied in detail using XRD and temperature-programmed reaction spectroscopy. The aim of this work was to improve the knowledge of the formation of the active phases or active sites of the catalysts from their precursors under the condition of the ammoxidation reaction. Similar catalytic properties of various applied VPO materials were discussed in terms of the presence of similar structure elements (domains of adjacent edge-sharing VO₆ octahedra-units and P-O-NH₄ groups).     

Effect of stepper lens operating conditions on proximity effects in DUV optical lithography down to 250nm

Reduction of optical proximity effects (OPE), at deep uv wavelength of 248nm, caused by the variation of stepper lens operating conditions is investigated. It is shown that many of these effects, which increase as the Rayleigh limit is approached, can be minimised, and in many cases eliminated, by suitable choice of lens numerical aperture (NA) and partial coherence (sigma, σ).

Application of these results should enable the user of advanced wafer steppers to carry out high resolution lithography with a minimum of time consuming optical proximity correction (OPC).