Riverine nitrogen distribution is increasingly controlled by anthropogenic activities in their watersheds, regardless of spatial scale, climate, and geographical zone. Consequently, modelling efforts to predict the export of nitrogen from rivers worldwide have used attributes such as population density, land use, urbanization and sanitation. These models have greatly enhanced our understanding ...

inulin is widely used in functional foods throughout the world for its health-promoting and technological properties. helianthus tuberosus is cultivated widely in the northern part of iran. helianthus tuberosus can be a valuable source of inulin. to optimize conventional extraction of inulin, various combinations of time, temperature, and solvent: solid ratio, were used. in this research, a ser...

Quantitative studies of the dissolved nitrogen in man have been previously made only for short periods of time, chiefly in determinations of cardiac output (Bornstein, 1919). Measurements of nitrogen absorption and elimination not only give an approximation of cardiac output, but also a’fford a representation of the absorption and elimination of all chemically inert gases, specifically the inha...

This paper aims to provide a review of the analytical extraction techniques for polycyclic aromatic hydrocarbons (PAHs) in soils. The extraction technologies described here include Soxhlet extraction, ultrasonic and mechanical agitation, accelerated solvent extraction, supercritical and subcritical fluid extraction, microwave-assisted extraction, solid phase extraction and microextraction, ther...

Access to bioavailable nitrogen often limits primary production in marine and freshwater ecosystems. Around 70% of nitrogen transported by rivers worldwide consists of dissolved organic nitrogen (DON), but its bioavailability has been poorly investigated. To assess the potential bacterial growth on DON, we developed a bioassay employing natural DON and bacterial inocula in medium manipulated to...

A laboratory experiment was performed to examine the remobilization of indicator polychlorinated biphenyls (iPCBs) from sediments and its results were applied to the real-world data for explaining the transport of PCBs in river. Seven PCB concentrations were determined in three series of model water-sediment systems (3 g of river sediment, three different volumes of distilled water (0.5, 0.25, ...

High-precision nitrogen NMR shieldings, bulk susceptibility corrected, are reported for dimethyl-N-nitrosamine (I) and diethyl-N-nitrosamine (II) in a variety of solvents which represent a wide range of solvent properties from the point of view of polarity as well as hydrogen bond donor and acceptor strength. The observed range of solvent-induced nitrogen shielding variations of (I) and (II) is...

Gloriosa superba is a medicinal plant used in traditional medicine for the treatment of various diseases. The tuber of Gloriosa superba is a rich source of colchicine which is used for the treatment of gout, cirrhosis and also used in plant breeding studies to produce polyploidy. Optimization of various extraction parameters using response surface methodology (RSM) was performed to assess maxim...