‘Green’ synthesis and optical properties of silver–chitosan complexes and nanocomposites

Silver nanoparticles were synthesized in a chitosan biopolymer by an in situ ‘green’ chemical procedure, using d-glucose as the reducing agent. The reaction intermediates (silver–chitosan complexes) as well as the obtained nanocomposites were investigated using transmission electron microscopy, UV–vis, FTIR and photoluminescence spectroscopy. The theoretical analysis of the UV–vis absorption of the Ag–chitosan complexes suggested that the significant contribution to the complex spectrum arises from clusters of silver containing 4–9 atoms. The absorption spectrum of the nanocomposite exhibited a strong surface plasmon resonance band at 406 nm. The photoluminescence behavior of the pure chitosan, the silver–chitosan complexes and the nanocomposites were discussed in terms of morphology and silver weight content.     

Investigation of the physico‐mechanical properties of electrospun PVDF/cellulose (nano)fibers

The electro‐activity and mechanical properties of PVDF depends mainly on the β‐phase content and degree of crystallinity. In this study, cellulose fibers were used to improve these characteristics. This could be achieved because the hydroxyl groups on cellulose would force the fluorine atoms in PVDF to be in the trans‐conformation, and the cellulose particles could act as nucleation centers. Electrospinning was used to prepare the PVDF/cellulose (nano)fibrous films, and this improved the total crystallinity and the formation of β‐crystals. However, the presence and amount of cellulose in PVDF were found to have little influence on the β‐phase content and on the total crystallinity of PVDF. Improvements in the extent of crystallinity and the β‐phase content were primarily brought about by the chain‐ and crystal orientation as a result of electrospinning. The thermal stability of PVDF in the composites slightly increased with increasing cellulose content in the composites up to 1.0 wt %, while the modulus and tensile strength significantly increased up to the same filler level. The dielectric storage permittivity also increased with increasing cellulose content, but the presence of cellulose had no influence on the dynamics of the γ‐ and β‐relaxations of the PVDF. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43594.     

Prevention of Clostridium outgrowth in heated and hermetically sealed meat products by nitrite – a review

This paper discusses several hypotheses regarding the inhibition of Clostridium in cured meat. It focuses on the binding of iron, as there is some evidence that inhibition of Clostridium botulinum outgrowth in nitrite-cured meat products is mainly due to iron binding in such a way that it is no longer available for outgrowth of Clostridium spores. This strong binding also explains the antioxidative properties of nitrite in these products. The binding of iron, in all probability, requires no more than a moderate amount of nitrite which, after binding as nitric oxide to the haem group, is unavailable for reactions leading to N-nitroso compounds either. Other reactions of nitrite, which also could lead to Clostridium inhibition, are not discussed in detail here.     

Stability of sulphadimidine during raw fermented sausage preparation: reaction of sulphadimine with nitrite

 Raw fermented sausage was prepared from a dough to which sulphadimidine (SDM), a drug frequently used in animal husbandry, was added. With the aid of thermospray-mass spectroscopy further evidence was obtained that, during preparation, reactions with nitrite added to the dough resulted in the formation of desamino-SDM and 4-hydroxydesamino-SDM. An indication was obtained that traces of chlorodesamino-SDM were present in the brine, but this observation could not be established. Received: 22 March 1999 / Revised version: 10 May 1999     

Theoretical claims necessitate basic research: Reply to Gawronski, Lebel, Peters, and Banse (2009) and Nosek and Greenwald (2009).

The authors of this reply article note that B. Gawronski, E. P. LeBel, K. R. Peters, and R. Banse (see record 2009-05290-002) (a) expressed agreement in their comment with the analysis put forward in the target article (J. De Houwer, S. Teige-Mocigemba, A. Spruyt, & A. Moors) (see record 2009-05290-001) and (b) pointed to a further implication for the way in which the implicitness of a measure should be examined. The current authors note that B. A. Nosek and A. G. Greenwald (see record 2009-05290-003), on the other hand, raised questions in their comment about the definition of the concept “implicit” in the target article, arguing for a fundamentally different approach to measurement that emphasizes not theoretical understanding but usefulness for predicting behavior. In this reply, the current authors respond to these comments and argue that when theoretical claims are made about measures, these claims should be backed up with appropriate evidence. In the absence of basic research, measures and their relation to behavior can only be described. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimal orientation in flows: providing a benchmark for animal movement strategies

Animal movements in air and water can be strongly affected by experienced flow. While various flow-orientation strategies have been proposed and observed, their performance in variable flow conditions remains unclear. We apply control theory to establish a benchmark for time-minimizing (optimal) orientation. We then define optimal orientation for movement in steady flow patterns and, using dynamic wind data, for short-distance mass movements of thrushes (Turdus sp.) and 6000 km non-stop migratory flights by great snipes, Gallinago media. Relative to the optimal benchmark, we assess the efficiency (travel speed) and reliability (success rate) of three generic orientation strategies: full compensation for lateral drift, vector orientation (single-heading movement) and goal orientation (continually heading towards the goal). Optimal orientation is characterized by detours to regions of high flow support, especially when flow speeds approach and exceed the animal''s self-propelled speed. In strong predictable flow (short distance thrush flights), vector orientation adjusted to flow on departure is nearly optimal, whereas for unpredictable flow (inter-continental snipe flights), only goal orientation was near-optimally reliable and efficient. Optimal orientation provides a benchmark for assessing efficiency of responses to complex flow conditions, thereby offering insight into adaptive flow-orientation across taxa in the light of flow strength, predictability and navigation capacity.     

Coordination by design and the price of autonomy

We consider a multi-agent planning problem as a set of activities that has to be planned by several autonomous agents. In general, due to the possible dependencies between the agents’ activities or interactions during execution of those activities, allowing agents to plan individually may lead to a very inefficient or even infeasible solution to the multi-agent planning problem. This is exactly where plan coordination methods come into play. In this paper, we aim at the development of coordination by design techniques that (i) let each agent construct its plan completely independent of the others while (ii) guaranteeing that the joint combination of their plans always is coordinated. The contribution of this paper is twofold. Firstly, instead of focusing only on the feasibility of the resulting plans, we will investigate the additional costs incurred by the coordination by design method, that means, we propose to take into account the price of autonomy: the ratio of the costs of a solution obtained by coordinating selfish agents versus the costs of an optimal solution. Secondly, we will point out that in general there exist at least two ways to achieve coordination by design: one called concurrent decomposition and the other sequential decomposition. We will briefly discuss the applicability of these two methods, and then illustrate them with two specific coordination problems: coordinating tasks and coordinating resource usage. We also investigate some aspects of the price of autonomy of these two coordination methods.     

万桥园

<正>序生命之路——致"万桥园"每座园林都有一个故事。它们是诗,在诉说。我们的园林讲述的是生命的故事,人的生命之路。这条路跌宕起伏,忍辱负重,讲述了忧愁河上的众桥。在这座园林中,生命是一条绵延不绝的蜿蜒小路,更恍如一座迷宫。     

Dissolved Silicon and Its Origin in Belgian Beers—A Multivariate Analysis

Beer is a quintessential part of Belgian heritage. We performed a detailed analysis of factors controlling Si content in Belgian beers as a case study to coincide with the 2011 IBiS meeting in Antwerp (Belgium). Beer is one of the richest dietary sources of Si. Three decades of research have yielded evidence of a role for Si in human physiology: it plays an essential role in bone mineral density and reduces the biological availability of aluminium. We analysed 119 Belgian beers: highest dissolved Si concentrations were found in high fermentation, traditionally brewed ales. Concentrations ranged between 214 and 2,071 μmol L^???1. This is probably due to the complexity and length of the brewing procedure: longer, more complicated processing and presence of brewing sediment in the bottle allows more Si to dissolve out of the base products like hop, barley or even rice. As a side effect of fermentation, alcohol content was related to Si content.     

Structure and properties of a β‐nucleated polypropylene impact copolymer

The effect of a β‐nucleating agent (β‐NA) on the properties and structure of a commercial impact polypropylene copolymer (IPC) was investigated. The effect of selected β‐NAs on the impact resistance, stress and strain behaviour of the IPC is reported. In addition, the IPC was fractionated according to crystallinity by preparative temperature rising elution fractionation. Fractions with varying chemical composition and crystallinity were treated with a two‐component β‐NA to investigate the effect of the β‐NA on the various fractions. The results indicate that the efficacy of the β‐NA is dependent on the chemical composition of the polymer that crystallises, more specifically on the sequence length of crystallisable propylene units. The effect of the addition of β‐NAs on the overall morphology of the IPC was also investigated, and in particular the size and distribution of the rubbery particles in these complex reactor blends were probed. © 2014 Society of Chemical Industry