CO2‐assisted polymer processing: A new alternative for intractable polymers

CO₂‐assisted polymer processing is proposed as an alternative route for intractable and high molecular weight polymers based on the plasticization effects of CO₂ and its direct effect on the melting behavior of semicrystalline polymers. A modified processing system was used to process a variety of polymers in the presence of high‐pressure CO₂. The system includes an extruder that was modified to allow for high pressures created by the injection of CO₂. The new design includes a modified feed section that allows a given mass of polymer to interact with CO₂ before and during the extrusion process. The inherent shear mixing and the presence of CO₂ allow for a specific control over the extrudate morphology. Results suggest that this alternative design provides a new and easy route to melt process high melt viscosity polymers of commercial importance, such as polytetrafluoroethylene (PTFE), fluorinated ethylene propylene copolymer (FEP), and syndiotactic polystyrene (s‐PS). The increased processability of these systems in CO₂ is related to the plasticization effect of CO₂ that was quantified through a depression in the glass‐transition temperature according to the Chow model. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1501–1511, 2004     

Mit zweierlei Maß: Die mangelnde Verbindlichkeit von Patientenverfügungen bei untergebrachten Personen mit psychischen Störungen in der Schweiz

Definition of the problem

Full age patients with mental disorders and preserved decision-making capacity are increasingly interested in drafting advance directives. Whereas in Switzerland (as well as in Germany) advance directives are binding in principle, an advance directive is not binding and has only to be considered in case of involuntary admission due to a mental disorder. Thereby, the virtual aim of an advance directive – the anticipated self-determination – is questioned.

Arguments

From an ethical perspective, patients with mental disorders have the same rights as patients with somatic diseases. Therefore, the question arises if there are good reasons for this unequal treatment. In the present contribution, four possible reasons are analyzed: (1) persons with mental disorders are “different”; (2) protection from self-harm; (3) often not present end-of-life context; (4) reduced bindingness as the more appropriate standard in general.

Conclusion

The authors come to the conclusion that patients with mental disorders are often capable of composing a valid advance directive, and just as any other human being, they have a principal and binding right for self-determination, even though they are particularly vulnerable in crisis situations.

     

Tailoring new bisphenol a ethoxylated shape memory polyurethanes

Shape memory polyurethanes (SMPUs) have generated great attention because of their unique properties. These properties are result of a particular molecular structure consisting of flexible molecular chains with low glass transition temperatures alternating with hard urethane segments. In this field, bisphenol A (BA) has been used for a long time as chain extender due to the good properties of the obtained SPMU materials. Nevertheless, the high toxicity of this compound has caused a high decrease on its use. For this reason, it has been selected a lower toxicity compound, bisphenol A ethoxylate (BAE). In this work, it is described a new SMPUs based on BAE and the influence of the hard segment on the thermo-mechanical properties and shape memory capacity. For that, both the proportion of the components and the diisocyanate employed (2,4-toluene diisocyanate (TDI), 4,4′-methylene bis(phenylisocyanate) (MDI) or a TDI/MDI mixture) have been modified. Then, depending on the molecular architecture achieved, the polyurethanes present different properties, which were studied by different techniques, such as thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic-mechanical thermal analysis (DMTA). It has been observed that glass transition temperature (T_g) increases as the hard phase content in the PU samples increases. In addition, T_g-MDI > T_g-MDI-TDI > T_g-TDI, so it is possible to control the T_g of the material, that is, shape memory transition temperature varying the diisocyanate. Finally, the shape memory capacity of the PUs was evaluated by thermo-mechanical analysis (TMA). All the synthesized PUs have shown good shape memory effect with fixation ratios up to 80% and recovery ratios close to 100%.     

Extended Reflexive Ontologies for the Generation of Clinical Recommendations

Decision recommendations are a set of alternative options for clinical decisions (e.g., diagnosis, prognosis, treatment selection, follow-up, and prevention) that are provided to decision makers by knowledge-based Clinical Decision Support Systems (k-CDSS) as aids. We propose to follow a “reasoning over domain” approach for the generation of decision recommendations by gathering and inferring conclusions from production rules. In order to rationalize our approach, we present a specification that will sustain the logic models supported in the knowledge bases we use for persistence. We introduce first the underlying knowledge model and then the necessary extensions that will convey toward the solution of the reported needs. The starting point of our approach is the proposition of Reflexive Ontologies (RO). Here, we go a step further, proposing an extension of RO that includes the handling and reasoning that production rules provide. Our approach speeds up the recommendation generation process.     

Real time motion estimation using a neural architecture implemented on GPUs

This work describes a neural network based architecture that represents and estimates object motion in videos. This architecture addresses multiple computer vision tasks such as image segmentation, object representation or characterization, motion analysis and tracking. The use of a neural network architecture allows for the simultaneous estimation of global and local motion and the representation of deformable objects. This architecture also avoids the problem of finding corresponding features while tracking moving objects. Due to the parallel nature of neural networks, the architecture has been implemented on GPUs that allows the system to meet a set of requirements such as: time constraints management, robustness, high processing speed and re-configurability. Experiments are presented that demonstrate the validity of our architecture to solve problems of mobile agents tracking and motion analysis.     

Improving the Control Energy in Model Reference Adaptive Controllers Using Fractional Adaptive Laws

This paper presents the analysis of the control energy consumed in model reference adaptive control (MRAC) schemes using fractional adaptive laws, through simulation studies. The analysis is focused on the energy spent in the control signal represented by means of the integral of the squared control input (ISI). Also, the behavior of the integral of the squared control error (ISE) is included in the analysis. The orders of the adaptive laws were selected by particle swarm optimization (PSO), using an objective function including the ISI and the ISE, with different weighting factors. The results show that, when ISI index is taken into account in the optimization process to determine the orders of adaptive laws, the resulting values are fractional, indicating that control energy of the scheme might be better managed if fractional adaptive laws are used.      

High‐Order Recursive Filtering of Non‐Uniformly Sampled Signals for Image and Video Processing

We present a discrete‐time mathematical formulation for applying recursive digital filters to non‐uniformly sampled signals. Our solution presents several desirable features: it preserves the stability of the original filters; is well‐conditioned for low‐pass, high‐pass, and band‐pass filters alike; its cost is linear in the number of samples and is not affected by the size of the filter support. Our method is general and works with any non‐uniformly sampled signal and any recursive digital filter defined by a difference equation. Since our formulation directly uses the filter coefficients, it works out‐of‐the‐box with existing methodologies for digital filter design. We demonstrate the effectiveness of our approach by filtering non‐uniformly sampled signals in various image and video processing tasks including edge‐preserving color filtering, noise reduction, stylization, and detail enhancement. Our formulation enables, for the first time, edge‐aware evaluation of any recursive infinite impulse response digital filter (not only low‐pass), producing high‐quality filtering results in real time.     

Proteomics in aortic aneurysm – What have we learnt so far?

Aortic aneurysm is a deceptively indolent disease that can cause severe complications such as aortic rupture and dissection. In the normal aorta, vascular smooth muscle cells within the medial layer produce and sustain the extracellular matrix (ECM) that provides structural support but also retains soluble growth factors and regulates their distribution. Although the ECM is an obvious target to identify molecular processes leading to structural failure within the vessel wall, an in-depth proteomics analysis of this important sub-proteome has not been performed. Most proteomics analyses of the vasculature to date used homogenized tissue devoid of spatial information. In such homogenates, quantitative proteomics comparisons are hampered by the heterogeneity of clinical samples (i.e. cellular composition) and the dynamic range limitations stemming from highly abundant cellular proteins. An unbiased proteomics discovery approach targeting the ECM instead of the cellular proteome may decipher the complex, multivalent signals that are presented to cells during aortic remodelling. A better understanding of the ECM in healthy and diseased vessels will provide important pathogenic insights and has potential to reveal novel biomarkers.     

Interior-point methods for symmetric optimization based on a class of non-coercive kernel functions

In this paper, we generalize polynomial-time primal–dual interior-point methods for symmetric optimization based on a class of kernel functions, which is not coercive. The corresponding barrier functions have a finite value at the boundary of the feasible region. They are not exponentially convex and also not strongly convex like many usual barrier functions. Moreover, we analyse the accuracy of the algorithm for this class of functions and we obtain an upper bound for the accuracy which depends on a parameter of the class.     

Variable Structure Control with chattering elimination and guaranteed stability for a generalized T-S model

In this paper, a fuzzy based Variable Structure Control (VSC) with guaranteed stability is presented. The main objective is to obtain an improved performance of highly non-linear unstable systems. The main contribution of this work is that, firstly, new functions for chattering reduction and error convergence without sacrificing invariant properties are proposed, which is considered the main drawback of the VSC control. Secondly, the global stability of the controlled system is guaranteed.The well known weighting parameters approach, is used in this paper to optimize local and global approximation and modeling capability of T-S fuzzy model.A one link robot is chosen as a nonlinear unstable system to evaluate the robustness, effectiveness and remarkable performance of optimization approach and the high accuracy obtained in approximating nonlinear systems in comparison with the original T-S model. Simulation results indicate the potential and generality of the algorithm. The application of the proposed FLC-VSC shows that both alleviation of chattering and robust performance are achieved with the proposed FLC-VSC controller. The effectiveness of the proposed controller is proven infront of disturbances and noise effects.