Synthesis,characterization, and photoresponsive behavior of new azobenzene‐containing polyethers

Two new polyethers, bearing azobenzene moiety in the side chain, were synthesized in excellent yields by means of anionic polymerization of 4‐glycidyloxyazobenzene and 4‐cyano‐4′‐glycidyloxyazobenzene (leading to azo‐P1 and azo‐P2 polymers, respectively) with the system polyiminophosphazene base t‐Bu‐P₄/3,5‐di‐tert‐butylphenol as initiator. The polymers were characterized with respect to their molecular weights, structure, and calorimetric features. The polyether bearing cyanoazobenzene group in the side chain was found to exhibit nematic phase up to 200 °C. E–Z isomerization of both polymers in tetrahydrofuran solution, after irradiating with UV light at 364 nm for 15 min, was investigated by means of UV–visible absorption spectroscopy. In the case of glycidylic monomers as well as the resulting polymers, E–Z isomerization was also investigated by means of ¹H NMR, by direct irradiation in the NMR probe in deuterated 1,1,2,2‐tetrachloroethane solution. By this technique, in the case of 4‐cyano‐4′‐glycidyloxyazobenzene, it was found that irradiation led to a photostationary state corresponding to an amount of Z isomer equal to 25%. For azo‐P1 polymer, Z–E or “reverse” isomerization was investigated at 60, 70, or 80 °C directly in the NMR probe; as expected, the process followed a first‐order rate law. The kinetic constants as well as the activation energy for the process were determined in this temperature range. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5426–5436, 2009     

Bounded BCK‐algebras and their generated variety

In this paper we prove that the equational class generated by bounded BCK‐algebras is the variety generated by the class of finite simple bounded BCK‐algebras. To obtain these results we prove that every simple algebra in the equational class generated by bounded BCK‐algebras is also a relatively simple bounded BCK‐algebra. Moreover, we show that every simple bounded BCK‐algebra can be embedded into a simple integral commutative bounded residuated lattice. We extend our main results to some richer subreducts of the class of integral commutative bounded residuated lattices and to the involutive case. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Quantum SUSY signatures in low and high energy processes

In the search for phenomenological evidence of supersymmetry through the indirect method of quantum signatures, it is useful to seek correlations of the non-standard quantum effects in low and high energy proceses, such as those involving on one hand the properties of theB-mesons and on the other hand the physics of the top quark and of the Higgs bosons. There are regions of the MSSM parameter space where the potential quantum SUSY signatures in the two energy regimes are strongly interwoven and therefore the eventual detection of these correlated quantum effects would strongly point towards the existence of underlying supersymmetric dynamics.     

Electrical conductivity in vinyl chloride during polymerization

Vinyl chloride of good polymerization quality showed a measurable electrical conductivity. The ionic strength of redistilled VCM appeared to be independent of temperature in the range from 20 to 50°C, and to decrease at higher temperatures. Conductivity measurements during bulk polymerization of VCM showed that the conductivity decreased with conversion. Other results indicated that electrolytically active species, formed during the polymerization, were trapped in the polymer matrix.     

Training humans in non-native phoneme perception using a monkey psychoacoustic procedure

Humans were trained to categorize problem non-native phonemes using an animal psychoacoustic procedure that trains monkeys to greater than 90% correct in phoneme identification [Sinnott and Gilmore, Percept. Psychophys. 66, 1341-1350 (2004)]. This procedure uses a manual left versus right response on a lever, a continuously repeated stimulus on each trial, extensive feedback for errors in the form of a repeated correction procedure, and training until asymptotic levels of performance. Here, Japanese listeners categorized the English liquid contrast /r-l/, and English listeners categorized the Middle Eastern dental-retroflex contrast /d-D/. Consonant-vowel stimuli were constructed using four talkers and four vowels. Native listeners and phoneme contrasts familiar to all listeners were included as controls. Responses were analyzed using percent correct, response time, and vowel context effects as measures. All measures indicated nativelike Japanese perception of /r-l/ after 32 daily training sessions, but this was not the case for English perception of /d-D/. Results are related to the concept of "robust" (more easily recovered) versus "fragile" (more easily lost) phonetic contrasts [Burnham, Appl. Psycholing. 7, 207-240 (1986)].     

The educational needs and professional roles of Canadian physicians and nurses regarding genetic testing and adult onset hereditary disease

OBJECTIVE: To investigate the knowledge, professional involvement and confidence of Canadian nurses and physicians in providing genetic services for adult onset hereditary disease. METHODS: 1,425 physicians and 1,425 nurses received a mailed questionnaire with reminders. The response rates were 50% (n = 543) and 79% (n = 975), respectively. RESULTS: Forty-eight percent of physicians and 31% of nurses lacked formal education in genetics. Respondents reported being involved in caring for people at risk for adult onset hereditary disease. Their levels of confidence that they could perform tasks, such as counselling about predictive genetic tests, however, were lower than their levels of expectation that it would be important for them to provide these services. CONCLUSIONS: The expected roles and educational needs of Canadian nurses and physicians have broad areas of overlap suggesting the possibility of combined professional education programs and multiple ways of organizing teams to provide genetic services to people at risk for adult onset hereditary disease.     

Data fusion methodologies for food and beverage authentication and quality assessment – A review

The ever increasing interest of consumers for safety, authenticity and quality of food commodities has driven the attention towards the analytical techniques used for analyzing these commodities. In recent years, rapid and reliable sensor, spectroscopic and chromatographic techniques have emerged that, together with multivariate and multiway chemometrics, have improved the whole control process by reducing the time of analysis and providing more informative results. In this progression of more and better information, the combination (fusion) of outputs of different instrumental techniques has emerged as a means for increasing the reliability of classification or prediction of foodstuff specifications as compared to using a single analytical technique. Although promising results have been obtained in food and beverage authentication and quality assessment, the combination of data from several techniques is not straightforward and represents an important challenge for chemometricians. This review provides a general overview of data fusion strategies that have been used in the field of food and beverage authentication and quality assessment.     

From the N‐Heterocyclic Carbene‐Catalyzed Conjugate Addition of Alcohols to the Controlled Polymerization of (Meth)acrylates

Among various N‐heterocyclic carbenes (NHCs) tested, only 1,3‐bis(tert‐butyl)imidazol‐2‐ylidene (NHC^tBu) proved to selectively promote the catalytic conjugate addition of alcohols onto (meth)acrylate substrates. This rather rare example of NHC‐catalyzed 1,4‐addition of alcohols was investigated as a simple means to trigger the polymerization of both methyl methacrylate and methyl acrylate (MMA and MA, respectively). Well‐defined α‐alkoxy poly(methyl (meth)acrylate) (PM(M)A) chains, the molar masses of which could be controlled by the initial [(meth)acrylate]₀/[ROH]₀ molar ratio, were ultimately obtained in N,N‐dimethylformamide at 25 °C. A hydroxyl‐terminated poly(ethylene oxide) (PEO‐OH) macro‐initiator was also employed to directly access PEO‐b‐PMMA amphiphilic block copolymers. Investigations into the reaction mechanism by DFT calculations revealed the occurrence of two competitive concerted pathways, involving either the activation of the alcohol or that of the monomer by NHC^tBu.     

Mathematical modelling and the learning trajectory: tools to support the teaching of linear algebra

In this article we present a didactic proposal for teaching linear algebra based on two compatible theoretical models: emergent models and mathematical modelling. This proposal begins with a problematic situation related to the creation and use of secure passwords, which leads students toward the construction of the concepts of spanning set and span. The objective is to evaluate this didactic proposal by determining the level of match between the hypothetical learning trajectory (HLT) designed in this study with the actual learning trajectory in the second experimental cycle of an investigation design-based research more extensive. The results show a high level of match between the trajectories in more than half of the conjectures, which gives evidence that the HLT has supported, in many cases, the achievement of the learning objective, and that additionally mathematical modelling contributes to the construction of these linear algebra concepts.