On-line generation of cyanogen chloride in semiautomated determination of niacin and niacinamide in food products

The current AOAC procedure for semiautomated determination of niacin specifies the use of externally generated cyanogen bromide. Because of the safety concerns in handling this material, we investigated the use of an alternative system of generating cyanogen chloride in situ, using chloramine-T and potassium cyanide. Recovery studies conducted on 9 different food products yielded average recoveries of 101%. A repeatability study resulted in a measured coefficient of variation of 2.9%. The AOAC niacin method was compared with this semiautomated method; 115 paired analyses on 8 different food types over 6 separate analytical replications indicated no significant difference by a paired t-test at the 95% confidence level.     

Exploiting the potential of indigenous fruit trees: <Emphasis Type="Italic">Grewia tenax</Emphasis> (Forssk.) Fiori in Sudan

The small leaved white cross berry (Grewia tenax [Forssk.] Fiori) is a fruit-producing deciduous shrub or small tree of widespread occurrence in semi-arid and sub-humid tropical climates. Despite its well-recognized potential and high prices on local markets, there are no commercial plantations in Sudan. Wild plants have continuously been used to meet the growing commercial demand for their fruits. Recently, there has been an increased interest in finding alternative, potentially high-value cash crops to improve the income of small farmers who are currently depending upon growing and selling millet (Pennisetum glaucum [L.] R. Br.), sorghum (Sorghum bicolor [L.] Moench), sesame (Sesamum indicum L.), and groundnut (Arachis hypogaea L.). G. tenax has often been cited as a prime candidate for domestication as a useful horticultural plant. One major factor hampering this development is the limited and scattered knowledge available on this species. The purpose of this paper is to highlight the importance of G. tenax by providing information on its botanical and horticultural characteristics in the effort to promote its domestication and commercialization for regional and global markets.     

Obstbau in einer Oase

Al Hassa, gelegen in der Golfregion Saudi-Arabiens, ist eine der größten und ältesten Oasen des Mittleren Ostens. Neben der Ölindustrie ist die rasch anwachsende Bevölkerung traditionell mit dem Gartenbau verbunden, in erster Linie mit der Kultur der Dattelpalme. Das vorherrschende Wüstenklima mit langen, trocken-heißen Perioden sowie zurückgehende Süßwasserreserven schaffen zunehmende Probleme für die landwirtschaftliche Produktion. Dazu kommt eine immer stärker werdende Versalzung der Bewässerungsflächen aufgrund des salzhaltigen Bewässerungswassers. Im vorliegenden Artikel werden der Obstbau in der Oase Al Hassa vor dem Hintergrund der aktuellen Wasserproblematik beschrieben und mögliche Lösungsansätze aufgezeigt.     

Is soot composed predominantly of carbon clusters?

Soot generated from diesel fuel in a combustion tube is characterized by microanalysis, x-ray diffraction, chemical reactivity, and nuclear magnetic resonance to address the recent proposal of the significance of carbon clusters in soot. The data support a traditional model of soot as polynuclear aromatic compounds rather than as clusters of carbon atoms with minimal edge site density. The amounts of noncarbon atoms in the soot (hydrogen, oxygen, nitrogen, and sulfur) are commensurate with the edge density of the crystallites (2 by 2 nanometers) inferred from diffraction. The chemistry of soot, in being reduced by potassium metal and alkylated by alkyl iodides, is that known for aromatic compounds and not that anticipated for materials such as graphite, with a small fraction of carbon atoms on edges.     

Virulence and local adaptation of a horizontally transmitted parasite

Parasites are thought to maximize the number of successfully transmitted offspring by trading off propagule production against host survival. In a horizontally transmitted microparasitic disease in Daphnia, a planktonic crustacean, increasing geographic distance between host and parasite origin was found to be correlated with a decrease in spore production and virulence. This finding indicates local adaptation of the parasite, but contradicts the hypothesis that long-standing coevolved parasites are less virulent than novel parasites. Virulence can be explained as the consequence of balancing the positive genetic correlation between host mortality and strain-specific spore production.