Electrical conductivity of ferroelectric sodium vanadate,rubidium vanadate,cesium vanadate and their solid solutions

The d.c. electrical conductivity of sodium vanadate, rubidium vanadate, cesium vanadate and their solid solutions sodium-rubidium vanadate and sodium-cesium vanadate were studied by a two-probe method in the temperature range covering their transition points. The electrical conductivity shows sharp change at the phase transition temperature of these materials. In NaVO₃, RbVO₃ and CsVO₃, increase in d.c. conductivity is observed in the ferroelectric region while nonlinearities are observed above transition temperatures. In solid solutions, the activation energy in the paraelectric state is higher than that in the ferroelectric state and depends upon sodium concentration.     

Esterification and Transesterification of Renewable Chemicals

An overview is given of newly developed Lewis or Brønsted acid and base catalysts for esterification, transesterification and ester interchange reactions. The most relevant applications of these catalysts and reactions in the domain of renewable resources, in particular, oils and fats, are discussed.     

Note: ferrule-top atomic force microscope. II. Imaging in tapping mode and at low temperature

In a recent paper [D.Chavan et al., Rev. Sci. Instrum. 81, 123702 (2010)] we have demonstrated that ferrule-top cantilevers, obtained by carving the end of a ferruled fiber, can be used for contact mode atomic force microscopy in ambient conditions. Here we show that those probes can provide tapping mode images at both room and cryogenic temperatures (12 K).     

Valorisation of mango seed via extraction of starch: preliminary techno-economic analysis

Reducing environmental impacts and obtaining economic benefits based on utilisation of waste materials are drivers for the implementation of cleaner production policies and technologies in food processing industries. Starch is a very versatile material with a wide range of applications in the food, pharmaceutical, textile, paper, cosmetic and construction industries. In Ethiopia, starch is widely used in the textile industry. To meet the starch demand, the country imports approximately 45% of the starch used in the country. Consequently, it is imperative to find additional sources of starch that could substitute for the amount of starch that is currently being imported. Mango seeds, a waste material that is disposed of after consumption of mangos, were studied for potential use as an alternative resource for starch production. The results showed that starch extraction from mango seeds was facile and a good quality product was obtained. The present study is concerned with a techno-economic analysis for industrial production of starch from mango seeds. The study shows that extraction of starch from waste mango seeds is feasible: the project is financially viable with an accounting rate of return of 83% and a break-even analysis of 78% with a payback period of 2 years.     

Fibre-top atomic force microscope probe with optical near-field detection capabilities

We present a fibre-top probe fabricated by carving a tipped cantilever on an optical fibre, with the tip machined in correspondence of the fibre core. When approached to an optical prism illuminated under total internal reflection conditions, the tip of the cantilever detects the optical tunnelling signal, while the light coupled from the opposite end of the fibre measures the deflection of the cantilever. Our results suggest that fibre-top technology can be used for the development of a new generation of hybrid probes that can combine atomic force microscopy with scanning near field optical microscopy.     

The effect of an amphiphilic self‐assembled lipid lamellar phase on the relief of dry skin

Humectant and occlusive technologies have traditionally been used for the treatment of dry skin. Originally, non‐lamellar‐forming ingredients were used such as petrolatum but recent research has shown the advantage of using lamellar‐forming ingredients such as ceramides, pseudoceramides and phospholipids in the relief of dry skin. Nevertheless, the importance of using lipid‐phase transition inducers, such as long‐chain fatty acids, has not been studied clinically. The evaluation of a novel complex of lipophilic ingredients was of interest: cetyl alcohol, isostearyl isostearate, potassium cetyl phosphate, cetyl behenate and behenic acid. The combination of all these ingredients was shown to be more effective than any single component in water vapour transmission rate studies. This was thought to be owing to the formation of a unique structural organization of the lipids upon dry‐down from an O/W emulsion as was examined by X‐ray diffraction and optical microscopy. When evaluated clinically in a randomized double‐blind and vehicle‐controlled moisturization efficacy trial, this novel blend of ingredients was shown to not only improve the visible signs of skin dryness to a significantly greater extent than a comparable mineral oil‐containing vehicle but also then maintain a better skin condition during the regression no‐treatment phase of the study. This combination of ingredients offers a new technology option for the treatment of dry skin.     

Chemical,biochemical, and biological significance of polyphenols in cereals and legumes

Polyphenols in cereals and legumes have been receiving considerable attention largely because of their adverse influence on color, flavor, and nutritional quality. These compounds belong to the flavonoid and tannin groups and are mostly located in the seed coat or pericarp of the grains. The pearl millet flavonoids have been identified as C‐glycosylflavones by the combined use of paper chromatography and UV spectroscopy. Although nontoxic, physiological and nutritional significance of these compounds occurring in high amounts in the pearl millet grain are still not clearly understood. In view of aesthetic quality, bleaching of the millet grains in acidic solution is recommended. A large proportion of current assays involves spectrophotometry of tannin or its chromogen and tannin‐protein interaction. Sorghum and legume tannins have been characterized as condensed tannins. Several factors such as plant type, age of the plant or plant parts, stage of development, and environmental conditions govern the polyphenol contents in plants. Polyphenols are known to interact with proteins and form tannin‐protein complexes leading to either inactivation of enzymes or making proteins insoluble. These are implicated in decreasing the activities of digestive enzymes, protein and amino acid availabilities, mineral uptake, vitamin metabolism, and depression of growth. Polyphenols are known to cause certain ultrastructural changes in the different parts of experimental animals. A correlation between dietary tannins and occurrence of esophageal cancer has been established. Bird resistance and seed germination in food crops have been correlated to high contents of polyphenols. The antinutritional activity of polyphenols can be reduced by removing polyphenols from the grains by chemical treatments or removing pericarp and testa by pearling. Treatment of alkaline reagents and ammonia can remove 90% of the polyphenols. Supplementation of polyphenols‐rich diet with protein can alleviate the growth‐depressing effect of polyphenols.