N‐Oligo(3‐hydroxybutyrate)‐functionalized polypyrroles: towards bio‐erodible conducting copolymers

New copolymer materials have been prepared by chemical grafting of oligomeric 3‐hydroxybutyric acid (OHB) onto polypyrrole (PPy) derivatives. The influence of grafting density and molecular weight of OHB brushes on the physicochemical properties of prepared copolymers was investigated. PPy substrates were prepared by FeCl₃‐driven oxidative homopolymerization of N‐(2‐carboxyethyl)pyrrole or its copolymerization with pyrrole. The grafting method employed involved controlled anionic polymerization of β‐butyrolactone on pyrrole‐tethered potassium carboxylate active sites. Obtained PPy‐g‐OHB copolymers of varying grafting density and pendant polyester chain length were characterized and the observed structure–property relationships discussed. The impact of real time exposure to phosphate‐buffered saline environment was investigated and the residue products were characterized. Cross‐correlation of spectroscopic, thermal, electrical and elemental analysis data afforded comprehensive evaluation of the structure of prepared materials and their behaviour in hydrolytic medium. Erosion and degradation pathways have been identified, indicating ways to consciously tailor the physicochemical properties of these new biomimetic materials. © 2016 Society of Chemical Industry     

Difference equation matrix model (DEMM) for the control of wind turbines

In this paper, a new algorithm, difference equation matrix model (DEMM), in the framework of model predictive control (MPC) is introduced. Instead of the standard dynamic matrix control (DMC), which is based upon step response method that has been used in most research works, we propose a new approach based upon a DEMM for model prediction. It has shown that DEMM has proven to be less computational and thus faster than the original DMC for real time applications. Thus, the drawbacks of DMC for online identification or adaptive design could be avoided. The control of wind turbines is carried out in order to decrease the cost of wind energy by increasing the efficiency, and thus the energy capture, or by reducing structural loading and increasing the lifetimes of the components and turbine structures. Modeling of wind turbine has been carried out. Effect of noise and disturbance on the system has been also studied. The results obtained show that the proposed DEMM minimizes the effect of the disturbance and produces an accurate and smooth control. Significant improvements in the regulation of rotor speed at high wind speeds are obtained from the proposed DEMM, where control set points are obtained ahead of the disturbance, saving the turbine of the negative effects of them and thus increasing its lifetime. Copyright © 2012 John Wiley & Sons, Ltd.     

Influence of caring youth sport contexts on efficacy-related beliefs and social behaviors.

Understanding what factors influence positive youth development has been advocated by youth development researchers (P. L. Benson, 2006; J. S. Eccles & J. A. Gootman, 2002). Consequently, the purpose of this study was to examine whether perceptions of a caring youth sport context influenced prosocial and antisocial behavior through efficacy-related beliefs, that is, positive and negative affective self-regulatory efficacy (ASRE) and empathic self-efficacy (ESE). Multiethnic youths taking part in summer sport programs (N = 395) completed a questionnaire that measured perceptions of the caring climate, ESE, ASRE, and social behavior. Structural equation modeling was used to test whether ASRE and ESE mediated the relationship between caring and social behaviors. Findings revealed that perceptions of caring positively predicted ASRE and ESE. In turn, positive ASRE positively predicted ESE. Prosocial behaviors were positively linked to ESE, whereas antisocial behaviors were negatively predicted by positive ASRE. The results suggest that caring influences prosocial and antisocial behavior because such contexts develop youths' ability to monitor, manage, and control positive affect, which in turn enhances their belief in their ability to empathize. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Real-time heating and power characterization of cells in standard cell designs

In today's digital electronic integrated circuits device heating is one of the most critical issues. Overheating can cause failures in functionality and device malfunction. In certain circumstances overheating of ICs can cause physical destruction of the device itself. This paper introduces a solution to determine cell and gate heating curves across the standard cell IC's surface. The presented methodology and toolset is tightly integrated into standardized logic simulator engines thus providing digital circuit designers a low-level, cell-resolution temperature distribution map during logic simulations. Actual temperatures of each consisting cell of the design can be monitored throughout the whole logic simulation. By being able to monitor temperatures of digital cells during initial simulations, it allows us to detect hot-spots and overheating caused malfunctions far before manufacture. By using the spatial location and temperature magnitude of hot-spots acquired from the presented methodology, place and route (P&R) tools can be driven to change cell placement and routing in order to avoid heating caused failures. Additionally, cooling solutions can be developed using the simulated temperature maps of the IC's surface. This paper also presents various aspects of power characterization methods which were used throughout the experiments.     

Segmenting visitors of cultural events by motivation: A sequential non-linear clustering analysis of Italian Christmas Market visitors

Considering the importance of market segmentation as a marketing tool to determine promotional policies, this paper aims to contribute to the tourism literature using the two-level approach proposed by Vesanto and Alhoniemi (2000) as an alternative and effective method to conduct cluster analyses.For this purpose, an empirical study was conducted interviewing tourists who visited three different Christmas Markets in Northern Italy. The two-level approach is based on two clustering techniques used in sequence: a Self-Organizing Map (SOM) followed by a clustering algorithm. The Silhouette index (Rousseeuw, 1987) is used as a guideline during the second level in the selection process of both the best clustering techniques (between hierarchical and non-hierarchical) and the best partition.The analysis identified three cluster segments and this paper demonstrates the suitability of the clustering method adopted. In the discussion of the results, marketing and managerial implications are also highlighted.     

Multi‐phosphorylation of the Intrinsically Disordered Unique Domain of c‐Src Studied by In‐Cell and Real‐Time NMR Spectroscopy

Intrinsically disordered regions (IDRs) are preferred sites for post‐translational modifications essential for regulating protein function. The enhanced local mobility of IDRs facilitates their observation by NMR spectroscopy in vivo. Phosphorylation events can occur at multiple sites and respond dynamically to changes in kinase–phosphatase networks. Here we used real‐time NMR spectroscopy to study the effect of kinases and phosphatases present in Xenopus oocytes and egg extracts on the phosphorylation state of the “unique domain” of c‐Src. We followed the phosphorylation of S17 in oocytes, and of S17, S69, and S75 in egg extracts by NMR spectroscopy, MS, and western blotting. Addition of specific kinase inhibitors showed that S75 and S69 are phosphorylated by CDKs (cyclin‐dependent kinases) differently from Cdk1. Moreover, although PKA (cAMP‐dependent protein kinase) can phosphorylate S17 in vitro, this was not the major S17 kinase in egg extracts. Changes in PKA activity affected the phosphorylation levels of CDK‐dependent sites, thus suggesting indirect effects of kinase–phosphatase networks. This study provides a proof‐of‐concept of the use of real‐time in vivo NMR spectroscopy to characterize kinase/phosphatase effects on intrinsically disordered regulatory domains.     

Pulsed laser induced birefringence switching in a biopolymer matrix containing azo-dye molecules

All optical switching has been studied using the Optical Kerr Effect (OKE) configuration in a biopolymer matrix containing an azo-dye: the Disperse Orange 3 (DO3). The biopolymer system consisted of a deoxyribonucleic acid blended with cationic surfactant molecule cetyltrimethyl-ammonium chloride is suitable for optical quality thin film fabrication. The excitation beams inducing birefringence were delivered from a continuous wave laser at 532 nm and another nanosecond pulsed Nd: YAG laser. The birefringence was instantaneously monitored under crossed polarizer system by a weak non-absorbed light from a cw He-Ne laser working at 632.8 nm. Fast all optical switching process (in the range of microseconds) and excellent reversibility have been observed.     

Oxygenated compounds derived from glycerol for biodiesel formulation: Influence on EN 14214 quality parameters

The methyl esters of fatty acids (biodiesel) obtained via transesterification of vegetable oils or animal fats are an alternative to current fossil fuels. A large amount of glycerol as a by-product is generated in this process and new applications for this surplus need to be found. Thus, the transformation of glycerol into branched oxygen-containing compounds could be an interesting solution to provide an outlet for increasing glycerol stocks. In this work, several oxygenated compounds, obtained by transformation of glycerol via etherification, esterification and acetalisation, have been assessed as components for biodiesel formulation. Different quality parameters have been evaluated following the procedures listed in the EN 14214 European Standard for biodiesel specifications. These parameters have been correlated with the amount and chemical nature of oxygenated derivate present in the biodiesel. The best performance as component for biodiesel formulation has been achieved by the mixture of ethers produced via etherification of glycerol with isobutylene. The addition of these compounds has not only improved the low-temperature properties of biodiesel (i.e. pour point and cold filter plugging point) and viscosity, but also did not impair other important biodiesel quality parameters analyzed. Although most of the studied oxygenated derivates do not significantly improve any biodiesel property, they do not exert a significant negative effect either. Furthermore, all of them allow an enhancement of overall yield in the biodiesel production. Nevertheless, further improvement could be addressed with a better purification to reduce the presence of non-desired impurities such as di-isobutylenes and unreacted acetic acid, which have a negative influence especially in acid number and oxidation stability.     

Numerical analysis of the width of fracture process zone in concrete beams

There are two ways of modelling cracking in concrete structures using a finite element method (FEM). In the first concept crack is considered as densely distributed throughout the finite area of element. The alternative approach assumes an isolated sharp interelement crack. The first concept of microcracked band is often used during numerical computations of concrete structures and a crack band model can be applied in design practice where relatively simple methods of calculations are preferred. In this model the width of microcracked zone, which is called the width of fracture process zone, is the additional parameter of tensile concrete.In this paper, the influence of the fracture process zone width on numerical calculations in case of bent concrete beams is analyzed. The results of numerical simulations are presented and compared with those obtained during the experiment. The crack band model proposed by Hillerborg [Cement and Concrete Research, 6 (1976) 773–782] has been used in numerical calculations and six different widths of fracture process zone have been modelled in the analyzed specimen. When comparing the obtained FEM-results their significant differences according to the width of fracture process zone have been observed. On the basis of the performed analysis it may be concluded that the width of fracture process zone taken in numerical simulations does have an influence on FEM-results.     

Development and Validation of Europium-Sensitized Luminescence (ESL) Method for the Determination of Tetracycline Residues in Milk

The development of a fast and reliable screening method for the determination of tetracycline residues in milk is described and compared to high-performance liquid chromatography. The method is based on europium-sensitized luminescence: The emissive properties of the lanthanide cation are used as a fingerprint of europium (III) complexation with tetracycline. The optimization of the extraction and purification procedures provided a simple and convenient route to prepare stable tetracycline samples that can safely resist freezing cycles. The method is validated for the first time in milk matrix: The results show that accuracy and precision of the method meet complaints with the criteria of the Commission Decision 2002/657/EC. The proposed method has a false compliant rate (β error) lower than 5%.