Microcellular polymeric foams based on 1‐vinyl‐2‐pyrrolidone and butyl‐acrylate with tuned thermal conductivity

Microcellular polymers have been produced by ScCO₂ foaming, based on 1‐vinyl‐2‐pyrrolidone (VP) and butyl‐acrylate (BA). Three different copolymers were prepared, varying the compositions of VP and BA, following a simple radical polymerization process using an UV initiator. The samples a good foaming behavior and also excellent flexibility and handle ability, with expansion ratios between 1.53 and 1.72, and cell sizes in the microcellular range (below 5 µm). However, it was observed that the gas distribution and, consequently, the cellular structure inside the polymer foams was highly dependent on the VP and BA proportions, leading to very different thermal conductivity values, even for similar volume gas fraction values. These results were related to the copolymer nanostructuration, which seems to have an influence in the final pore structure, thus opening the possibility of designing microcellular foams with similar macroscopic characteristics but different thermal conductivity values. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45872.     

Proteomic mapping of 4-hydroxynonenal protein modification sites by solid-phase hydrazide chemistry and mass spectrometry

The modification of proteins by the cytotoxic, reactive aldehyde 4-hydroxynonenal (HNE) is known to alter protein function and impair cellular mechanisms. In order to identify susceptible amino acid sites of HNE modification within complex biological mixtures by microcapillary liquid chromatography and linear ion trap tandem mass spectrometry, we have developed a solid-phase capture and release strategy that utilizes reversible hydrazide chemistry to enrich HNE-modified peptides. To maximize the detection of fragment ions diagnostic of HNE modification, both neutral loss-dependent acquisition of MS/MS/MS spectra and the pulsed Q dissociation operation mode were employed. When the solid-phase hydrazide enrichment strategy was applied to a yeast lysate treated with HNE, 125 distinct amino acid sites of HNE modification were mapped on 67 different proteins. The endogenous susceptibility of many of these proteins to HNE modification was demonstrated by analyzing HNE-treated yeast cell cultures with a complementary biotin hydrazide enrichment strategy. Further analysis revealed that the majority of amino acid sites susceptible to HNE modification were histidine residues, with most of these sites being flanked by basic amino acid residues, and predicted to be solvent exposed. These results demonstrate the effectiveness of this novel strategy as a general platform for proteome-scale identification of amino acid sites susceptible to HNE modification from within complex mixtures.     

Who leads research productivity growth? Guidelines for R&D policy-makers

This paper evaluates to what extent policy-makers have been able to promote the creation and consolidation of comprehensive research groups that contribute to the implementation of a successful innovation system. Malmquist productivity indices are applied in the case of the Spanish Food Technology Program, finding that a large size and a comprehensive multi-dimensional research output are the key features of the leading groups exhibiting high efficiency and productivity levels. While identifying these groups as benchmarks, we conclude that the financial grants allocated by the program, typically aimed at small-sized and partially oriented research groups, have not succeeded in reorienting them in time so as to overcome their limitations. We suggest that this methodology offers relevant conclusions to policy evaluation methods, helping policy-makers to readapt and reorient policies and their associated means, most notably resource allocation (financial schemes), to better respond to the actual needs of research groups in their search for excellence (micro-level perspective), and to adapt future policy design to the achievement of medium-long term policy objectives (meso and macro-level).     

Reduction of Listeria monocytogenes, Salmonella spp., and Escherichia coli O157:H7 During Processing of Country-cured Hams

ABSTRACT: The country-cured ham process, including curing, equalization, cold-smoked or nonsmoked, and aging up to 6 mo, was validated and showed its effectiveness in achieving a 6-log reduction of Listeria monocytogenes, Salmonella spp., and Escherichia coli O157:H7. The viable counts of L. monocytogenes populations decreased to below detection levels after 206 d, Salmonella populations required 122 d, and E. coli O157:H7 required 66 d. However, L. monocytogenes -inoculated hams were positive and Salmonella spp-inoculated and E. coli O157:H7-inoculated hams were negative following enrichment procedures at the end of the aging process. Therefore, the survival of L. monocytogenes on country-cured ham represents a risk.     

Pretest-posttest field studies on psychological restoration: a descriptive review and reflections for the future

Almost four decades ago, Attention Restoration Theory and Stress Recovery Theory postulated that nature could help people to recover from the attentional fatigue and the emotional negative outcomes coming from their daily performance. Since then, these theories have inspired a great amount of research. In this review, 19 restoration pretest-posttest field studies were selected. A systematic analysis of the papers was conducted using two rating tools to assess the quality of the studies and to detect their main strengths and weaknesses. The results allowed us to synthesise the results of this sample of studies, to reflect about the nature of the research conducted until today and to point to some issues and challenges that might be addressed in future studies.     

Analysis of the Influence of Mill Helix Angle on Chatter Stability

Current methods for estimating chatter stability limits for milling do not consider the influence of the helix angle and the consequent phase lag between the forces appearing at different sections of the mill. Budak and Altintas' multifrequency solution is extended to include the helix effect, and results are compared with results of semi-discretization and experiments.As a conclusion, the helix has an important influence on the areas of added lobes (flip lobes), while the influence on the traditional lobes is negligible. Flip lobes become closed curves separated by horizontal lines where the depth of cut equals a multiple of the helix pitch.     

Analyzing the presence of noise in multi-class problems: alleviating its influence with the One-vs-One decomposition

The presence of noise in data is a common problem that produces several negative consequences in classification problems. In multi-class problems, these consequences are aggravated in terms of accuracy, building time, and complexity of the classifiers. In these cases, an interesting approach to reduce the effect of noise is to decompose the problem into several binary subproblems, reducing the complexity and, consequently, dividing the effects caused by noise into each of these subproblems. This paper analyzes the usage of decomposition strategies, and more specifically the One-vs-One scheme, to deal with noisy multi-class datasets. In order to investigate whether the decomposition is able to reduce the effect of noise or not, a large number of datasets are created introducing different levels and types of noise, as suggested in the literature. Several well-known classification algorithms, with or without decomposition, are trained on them in order to check when decomposition is advantageous. The results obtained show that methods using the One-vs-One strategy lead to better performances and more robust classifiers when dealing with noisy data, especially with the most disruptive noise schemes.     

What indicators do (or do not) tell us about Regional Innovation Systems

This paper analyses some of the methodologies and R&D and innovation indicators used to measure Regional Innovative Capacity in Spain for the period 1996–2000. The results suggest that the approaches examined are not sufficiently rigorous; they vary depending on the methodology and indicators employed. Therefore, we would suggest that the right balance between quantitative and qualitative approaches could produce a better evaluation of innovation system performance which would be more useful to policy makers and other stakeholders.