Applicability of light depolarization technique to crystallization studies

Critical analysis of light depolarization technique (LDT) widely used in polymer crystallization kinetics is presented. It is demonstrated, that intensity of light depolarized on a system of birefringent crystals cannot be treated as a measure of volume fraction of crystalline phase (degree of crystallinity). Intensity of light depolarized in a polycrystalline system is a non-linear function of the product of the degree of crystallinity and function of average crystal dimensions. Closed-form expression for depolarization ratio is derived and the range of conditions where linear approximation is acceptable is discussed.In spite of interpretational weaknesses, further development of light depolarization technique seems to be justified by potentially short response time. LDT may appear useful for studying rapid crystallization processes (above 1 kHz sampling frequency), which cannot be followed by measurements of density, X-ray diffraction or calorimetry. However, the LDT data either have to be combined with independent measurements of crystal thickness, or treated as a ‘crystallization characteristic’ per se, quantitatively inconsistent with calorimetric, volumetric or X-ray diffraction data.     

Building a new supply chain position: an exploratory study of companies in the timber housing industry

Innovation is an important source of growth for many companies. It is also challenging, as it may require that the companies build a new position in the supply chain. The literature is devoid of analysis of different ways to build such positions in the construction industry. The purpose here is to explore the challenges involved in implementing innovations that require companies to establish new positions in a construction supply chain. Three in‐depth case studies in the Swedish timber housing industry illustrate different challenges that arise with the different modes of repositioning of organic growth, collaboration and acquisition, and with moving either backward or forward in the supply chain. Organic growth is a slow process that prevents companies from taking a first‐mover advantage. Acquisitions can involve difficulties with exploiting acquired competences. Collaboration brings the risks of diversity of interests and transient solutions. Furthermore, and as shown in the cases studied, challenges are associated with pre‐existing competencies and relationships, with technology‐oriented companies facing customer‐related difficulties and market‐oriented companies mainly facing ones involving technological solutions. The construction industry’s idiosyncrasies amplify these challenges, as its fragmentation makes it difficult to connect with external companies at new positions. Stronger ties with business partners are likely to enable construction companies to exploit more easily innovations that require repositioning in the supply chain.     

The effect of wheat grain composition, cuticular lipids and kernel surface microstructure on feeding, egg-laying, and the development of the granary weevil, Sitophilus granarius (L.)

Adult feeding intensity, oviposition, and larval development of Sitophilus granarius (Coleoptera: Curculionidae) were observed on grain from three Polish wheat varieties (Begra, Korweta, and LGR 896/64a) washed with petroleum ether to remove cuticular lipids. Extraction of lipids did not cause any statistically significant changes in the physicochemical, biochemical and technological (milling, rheological and baking) properties of the wheat grain studied. Wheat grain washed with petroleum ether did not show any visible changes in the surface and morphology of the outer layer of the wheat grain. However, differences were noted in the microstructure of the kernel surface. Grain with a thicker seed coat (LGR 896/64a) was infested at a lower rate than the other varieties. Of the 18 hydrocarbons extracted from the grain surface, three compounds - n-heptacosane (C₂₇), n-nonacosane (C₂₉) and n-hentriacontane (C₃₁) - were found in significant amounts. In general, beetles produced 64-95% less dust and laid 7-16% fewer eggs in kernels from which cuticular lipids had been removed. This implies that these compounds have a major role in food selection and the search for an oviposition site prior to grain infestation.     

Tremendous reinforcing,pore‐stabilizing and response‐accelerating effect of in situ generated nanosilica in thermoresponsive poly(N‐isopropylacrylamide) cryogels

The tremendous reinforcing and pore‐stabilizing effect of in situ formed nanosilica in a highly porous temperature‐responsive poly(N‐isopropylacrylamide) (PNIPA) matrix is demonstrated. A very weakly crosslinked semi‐liquid hydrogel can be reinforced to the point that it displays a fast, extensive and nearly symmetric temperature‐responsiveness in combination with an acceptable modulus. In soft but solid porous PNIPA, only 0.6 wt% of the nanofiller is sufficient to stabilize the pores against collapse upon de‐swelling, thus enabling ultrafast responsiveness. A spectacular effect is achieved with dried porous PNIPA (matrix is glassy, T_g ≈ 140 °C), which in the case of optimal nanosilica amounts can re‐swell in only 3 min. The key importance of efficient hydrogen bridging between PNIPA and SiO₂ is demonstrated by comparing in situ formed nanosilica with similarly sized commercial Ludox particles, the surface of which is saturated with ammonia (for stabilization). Synthesis parameters like the amount of crosslinker and of nanosilica were varied in a wide range, in order to achieve the fastest possible responsiveness of the hydrogels in combination with a high modulus. The porosity, nanosilica distribution, moduli, temperature‐dependent swelling as well as the swelling kinetics of the gels were determined as functions of contents of crosslinker and nanosilica. © 2017 Society of Chemical Industry     

Research-informed evidence and support for road safety legislation: Findings from a national survey

Public opinion is influential in the policymaking process, making it important to understand the factors that influence popular support or opposition to public health policies. Researchers and policymakers tend to agree that scientific evidence can inform decision-making, but this influence has not been explored sufficiently, especially in the area of injury prevention. This paper considers the potential for the communication of evidence-based research and public health data to influence opinion about legislation that could reduce road-related injury. We conducted a nationally-representative online survey to assess public attitudes toward four road-safety laws; ignition interlock, school zone red-light cameras, restrictions on infotainment systems, and children's bicycle helmets. For each law, we assessed initial support and then provided a research-informed statistic on either the injury risk posed or the law's efficacy reducing risk and re-examined the law's support or opposition. The survey was completed by 2397 U.S. adults. Each law was initially supported by a majority of respondents, with greatest support for ignition interlock (74.4%) and children's bicycle helmets (74.8%). Exposure to research-informed statements increased legislative support for 20–30% of respondents. Paired analyses demonstrate significant increases toward supportive opinions when comparing responses to the initial and research-informed statements. The study demonstrates considerable public support for evidence-based road-related laws. Overall support was augmented by exposure to research data. Injury prevention practitioners can capitalize on this support in efforts to build support for legislation that would prevent injury. Researchers should be encouraged to expand their efforts to share research results with both the public and policymakers.     

Aromagrams – Aromatic profiles in the appreciation of food quality

In this review a new approach to the food aroma analysis using various instrumental techniques is described. In the last decade extensive studies have been performed concerning aroma profiles (called in this article ‘aromagrams’) of food products and beverages. Aromagram is characteristic or even individual fingerprint of the odour, obtained usually by chromatographic methods or electronic nose. Basing on the fact that each product has its own unique pattern of volatile components, it is possible to get desired information about organoleptic quality and health safety of the product by qualitative and quantitative comparison of aromagrams of different foodstuffs. Appearance of aromagrams and their usefulness depend on the assay method, particularly on the extraction step. The paper reviews the methods developed to analyse volatiles in food products basing upon their aroma profiles.     

Early Postnatal Exposure to a Low Dose of Nanoparticulate Silver Induces Alterations in Glutamate Transporters in Brain of Immature Rats

Due to strong antimicrobial properties, silver nanoparticles (AgNPs) are used in a wide range of medical and consumer products, including those dedicated for infants and children. While AgNPs are known to exert neurotoxic effects, current knowledge concerning their impact on the developing brain is scarce. During investigations of mechanisms of neurotoxicity in immature rats, we studied the influence of AgNPs on glutamate transporter systems which are involved in regulation of extracellular concentration of glutamate, an excitotoxic amino acid, and compared it with positive control—Ag citrate. We identified significant deposition of AgNPs in brain tissue of exposed rats over the post-exposure time. Ultrastructural alterations in endoplasmic reticulum (ER) and Golgi complexes were observed in neurons of AgNP-exposed rats, which are characteristics of ER stress. These changes presumably underlie substantial long-lasting downregulation of neuronal glutamate transporter EAAC1, which was noted in AgNP-exposed rats. Conversely, the expression of astroglial glutamate transporters GLT-1 and GLAST was not affected by exposure to AgNPs, but the activity of the transporters was diminished. These results indicate that even low doses of AgNPs administered during an early stage of life create a substantial risk for health of immature organisms. Hence, the safety of AgNP-containing products for infants and children should be carefully considered.     

A brief review on hydrometallurgical technologies for recycling spent lithium‐ion batteries

Lithium‐ion battery is a mature technology that is used in various electronic devices. Nowadays, this technology is a good candidate as energy storage for electric vehicles. Therefore, much research is focused on the development of high‐density power lithium‐ion batteries. Government regulations force manufacturers to recycle the batteries for safety and health reasons but recycling could also be interesting from an economic viewpoint since cathodes in lithium‐ion batteries contain valuable metals. The electrodes in lithium‐ion batteries will evolve to provide more energy and the recycling processes will have to fit with this evolution. Leaching, bioleaching and solvent extraction are at the centre of these processes. In this paper, recent leaching and solvent extraction strategies for recovering valuable metals from spent lithium‐ion batteries are reviewed and the evolution of these processes is discussed. © 2013 Society of Chemical Industry