Luminol chemiluminescence: Chemistry,excitation, emitter

The mechanism of luminol chemiluminescence is a special case of nucleophilic addition to carbonyl compounds. The breakdown of the key intermediate, an alpha hydroxy hydroperoxide, produces a peracid ortho to an acyl diazene group. After intramolecular addition of the peracid, the energy from nitrogen expulsion is utilized in the formation of an anti-aromatic endoperoxide. Rupture along the O,O bond leaves a substantial part of the ensuing phthalate in its excited state. The emitter is shown to be a mono-protonated phthalate unaccessible by photoexcitation. The dark reaction is a concerted decomposion of the alpha hydroxy hydroperodixe to yield ground-state phthalate.     

Glucoraphasatin: Chemistry, occurrence, and biological properties

Glucoraphasatin is an atypical glucosinolate mainly found in Raphanus sativus roots and sprouts. This review focuses on the chemistry, the occurrence, and the biological properties of glucoraphasatin.     

The Effects of Research & Development Funding on Scientific Productivity: Academic Chemistry, 1990-2009

This article examines the relationship between Research & Development (R&D) funding and the production of knowledge by academic chemists. Using articles published, either raw counts or adjusted for quality, we find a strong, positive causal effect of funding on knowledge production. This effect is similar across subsets of universities, suggesting a relatively efficient allocation of R&D funds. Finally, we document a rapid acceleration in the rate at which chemical knowledge was produced in the late 1990s and early 2000s relative to the financial and human resources devoted to its production.     

Potato Glycoalkaloids: Chemistry,Analysis, Safety,and Plant Physiology

Potatoes, members of the Solanaceae plant family, serve as a major, inexpensive food source for both energy (starch) and good-quality protein, with worldwide production of about 350 million tons per year. U.S. per capita consumption of potatoes is about 61 kg/year. Potatoes also produce potentially toxic glycoalkaloids, both during growth and after harvest. Glycoalkaloids appear to be more toxic to man than to other animals. The toxicity may be due to anticholinesterase activity of the glycoalkaloids on the central nervous system and to disruptions of cell membranes affecting the digestive system and other organs. The possible contribution of glycoalkaloids to the multifactorial aspects of teratogenicity is inconclusive. Possible safe levels are controversial; guidelines limiting glycoalkaloid content of potato cultivars are currently being debated. This review presents an integrated, critical assessment of the multifaceted aspects of the role glycoalkaloids play in nutrition and food safety; chemistry and analysis; plant physiology, including biosynthesis, distribution, inheritance, host-plant resistance, and molecular biology; preharvest conditions such as soil composition and climate; and postharvest events such as effects of light, temperature, storage time, humidity, mechanical injury, sprouting inhibition, and processing. Further research needs are suggested for each of these categories in order to minimize pre- and postharvest glycoalkaloid synthesis. The overlapping aspects are discussed in terms of general concepts for a better understanding of the impact of glycoalkaloids in plants and in the human diet. Such an understanding can lead to the development of potato varieties with a low content of undesirable compounds and will further promote the utilization of potatoes as a premier food source for animals and humans.     

The Sandfish＇s Skin： Morphology, Chemistry and Reconstruction

The sandfish is a lizard having the remarkable ability to move in desert sand in a swimming-like fashion. The most outstanding adaptations to this mode of life are the low friction behaviour and the extensive abrasion resistance of the sandfish skin against sand, outperforming even steel. We investigated the topography, the composition and the mechanical properties of sandfish scales. These consist of glycosylated keratins with high amount of sulphur but no hard inorganic material, such as silicates or lime. Remarkably, atomic force microscopy shows an almost complete absence of attractive forces between the scale surface and a silicon tip, suggesting that this is responsible for the unusual tribological properties. The unusual glycosylation of the keratins was found to be absolutely necessary for the described phenomenon. The scales were dissolved and reconstituted on a polymer surface resulting in properties similar to the original scale. Thus, we provide a pathway towards exploitation of the reconstituted scale material for future engineering applications.     

The Sandfish's Skin:Morphology,Chemistry and Reconstruction

The sandfish is a lizard having the remarkable ability to move in desert sand in a swimming-like fashion. The most out-standing adaptations to this mode of life are the low friction behaviour and the extensive abrasion resistance of the sandfish skin against sand, outperforming even steel. We investigated the topography, the composition and the mechanical properties of sandfish scales. These consist of glycosylated keratins with high amount of sulphur but no hard inorganic material, such as silicates or lime. Remarkably, atomic force microscopy shows an almost complete absence of attractive forces between the scale surface and a silicon tip, suggesting that this is responsible for the unusual tribological properties. The unusual glycosylation of the keratins was found to be absolutely necessary for the described phenomenon. The scales were dissolved and reconstituted on a polymer surface resulting in properties similar to the original scale. Thus, we provide a pathway towards exploitation of the reconstituted scale material for future engineering applications.