Preliminary Evidence on the Diagnostic and Molecular Role of Circulating Soluble EGFR in Non-Small Cell Lung Cancer

Assessment of biological diagnostic factors providing clinically-relevant information to guide physician decision-making are still needed for diseases with poor outcomes, such as non-small cell lung cancer (NSCLC). Epidermal growth factor receptor (EGFR) is a promising molecule in the clinical management of NSCLC. While the EGFR transmembrane form has been extensively investigated in large clinical trials, the soluble, circulating EGFR isoform (sEGFR), which may have a potential clinical use, has rarely been considered. This study investigates the use of sEGFR as a potential diagnostic biomarker for NSCLC and also characterizes the biological function of sEGFR to clarify the molecular mechanisms involved in the course of action of this protein. Plasma sEGFR levels from a heterogeneous cohort of 37 non-advanced NSCLC patients and 54 healthy subjects were analyzed by using an enzyme-linked immunosorbent assay. The biological function of sEGFR was analyzed in vitro using NSCLC cell lines, investigating effects on cell proliferation and migration. We found that plasma sEGFR was significantly decreased in the NSCLC patient group as compared to the control group (median value: 48.6 vs. 55.6 ng/mL respectively; p = 0.0002). Moreover, we demonstrated that sEGFR inhibits growth and migration of NSCLC cells in vitro through molecular mechanisms that included perturbation of EGF/EGFR cell signaling and holoreceptor internalization. These data show that sEGFR is a potential circulating biomarker with a physiological protective role, providing a first approach to the functional role of the soluble isoform of EGFR. However, the impact of these data on daily clinical practice needs to be further investigated in larger prospective studies.     

Understanding the dynamic behaviour of middle-vessel continuous distillation columns

The fundamental dynamic behaviour of a middle-vessel continuous distillation column is studied in this paper. The interaction between the middle vessel (MV) design and control parameters is identified by means of a linear analysis. Transfer functions relating the dynamics of the product composition responses to changes in the disturbance inputs and manipulated inputs are derived. The role of the MV holdup and MV level controller gain in altering the product composition responses is identified. It is shown that the MV level controller gain can significantly affect the control performance when feed flow disturbances must be compensated for. However, it has a much lower impact in the control performance when feed composition disturbances need to be rejected; in this case, exploiting the “buffering” effect of the MV is more important for control. The analysis is carried out in detail for a LV control configuration, and is subsequently extended to an “on-demand” DB configuration. Finally, simple guidelines for the choice of the MV level controller gain and MV holdup are provided.     

Performance and robustness of block constraint preconditioners in finite element coupled consolidation problems

Block constraint preconditioners are a most recent development for the iterative solution to large‐scale, often ill‐conditioned, coupled consolidation problems. A major limitation to their practical use, however, is the somewhat difficult selection of a number of user‐defined parameters (at least 4) in a more or less optimal way. The present paper investigates the robustness of three variants of the block constraint preconditioning in relation to the above parameters. A theoretical analysis of the eigenspectrum of the preconditioned matrix provides relatively simple bounds of the eigenvalues as a function of these parameters. A number of test problems used to validate the theoretical results show that both the mixed constraint preconditioner (MCP) combined with the symmetric quasi‐minimal residual (SQMR) solver and the MCP triangular variant (T‐MCP) combined with the bi‐conjugate gradient stabilized (Bi‐CGSTAB) are efficient and robust tools for the solution to difficult Finite Element‐discretized coupled consolidation problems. Moreover, the practical selection of the user‐defined parameters is relatively easy as a stable behavior is observed for a wide range of fill‐in degree values. The theoretical bounds on the eigenspectrum of the preconditioned matrix may help to suggest the most appropriate parameter combination. Copyright © 2009 John Wiley & Sons, Ltd.     

Photochromic Polymers Based on the Photoinduced Opening and Thermal Closing of [1,3]Oxazine Rings

Two macromolecular constructs incorporating a single polymer backbone with multiple photochromic side chains are developed. Both systems are prepared from preformed photochromic [1,3]oxazines after the ring‐opening polymerization of their norbornene appendages. In solution, UV illumination of these polymers opens the [1,3]oxazine rings in their side chains in less than 6 ns and with a quantum yield of 0.09 in both instances. The photogenerated species incorporate a 4‐nitrophenolate chromophore, and hence, their formation is accompanied by the appearance of an intense band in the visible region of the absorption spectrum. The photoproducts revert spontaneously to the original state with first‐order kinetics in microseconds. Furthermore, both photochromic polymers tolerate hundreds of switching cycles with no sign of degradation, even in the presence of molecular oxygen. Thus, this design logic and choice of functional building blocks can translate into the realization of innovative photoresponsive materials with excellent photochromic performance.     

Sustainable simultaneous communications in ad-hoc networks using smart antenna systems

This article proposes an analytical model for evaluating the number of simultaneous communications that can be sustained by an ad-hoc network in which the nodes are equipped with fully adaptive smart antennas. The presented mathematical framework adopts realistic models for the antenna radiation pattern and the channel behavior, and is able to take into account the network topology and the characteristics of the medium access control (MAC) protocol in the spatial domain. The model is employed to investigate the impact of the spatial channel model and of the angular spread on network performance. Additionally, this article examines the influence of the transmission policy of the control and data packets of the MAC layer on the number of simultaneous communications.     

Optimal selection of soft sensor inputs for batch distillation columns using principal component analysis

In this paper, a novel methodology based on principal component analysis (PCA) is proposed to select the most suitable secondary process variables to be used as soft sensor inputs. In the proposed approach, a matrix is defined that measures the instantaneous sensitivity of each secondary variable to the primary variables to be estimated. The most sensitive secondary variables are then extracted from this matrix by exploiting the properties of PCA, and they are used as input variables for the development of a regression model suitable for on-line implementation.This method has been evaluated by developing a soft sensor that uses temperature measurements and a process regression model to estimate on-line the product compositions for a simulated batch distillation process. The identification of the optimal soft sensor inputs for this case study has been discussed with respect to the definition of the sensitivity matrix, the data sampling interval, the presence of measurement noise, and the size of the input set. The simulation results demonstrate that the proposed approach can effectively identify the size and configuration of the input set that leads to the optimal estimation performance of the soft sensor.     

Application of the Kalman filter for electrical endurancecharacterization of insulating materials and systems

The Kalman filter algorithm is applied to the results of accelerated life tests performed on insulating materials and systems carried out for electrical endurance characterization purposes. It consists of a recursive procedure that applies to the failure-time percentiles obtained from life tests, on the basis of the inverse power or the exponential models, and provides estimates of the endurance indices which give particular weight to the results of the life tests performed at the lowest test stresses. This allows more meaningful endurance characterization and accurate life prediction. This paper provides the algorithms for Kalman filter applications, giving emphasis to error estimation, as well as the method for calculation of confidence limits of life-line parameters and predicted failure times. The proposed Kalman filter procedure is applied to the experimental results of accelerated life tests relevant to different insulating materials and systems     

A Formal Model for Video Shot Segmentation and its Application via Animate Vision

The first step in a video indexing process is the segmentation of videos into meaningful parts called shots. In this paper we present a formal model of the video shot segmentation process. Starting from a mathematical characterization of the most common transition effects, a video segmentation algorithm capable to detect both abrupt and gradual transitions is proposed. The proposed algorithm is based on the computation of an arbitrary similarity measure between consecutive frames of a video. The algorithm has been tested adopting a similarity metric based on the Animate Vision theory and results have been reported.