Natural dissolved organic matter (DOM) is the major absorber of sunlight in most natural waters and a critical component of carbon cycling in aquatic systems. The combined effect of light absorbance properties and related photo-production of reactive species are essential in determining the reactivity of DOM. Optical properties and in particular excitation-emission matrix fluorescence spectrosc...

Naturally-occurring organic material (NOM) in dissolved, colloidal and particulate forms is ubiquitous in surface and ground waters. NOM is a heterogeneous mixture of complex organic materials including humic substances, hydrophilic acids, proteins, lipids, carboxylic acids, polysaccharides, amino acids, and hydrocarbons [1]. The dissolved and colloidal forms (i.e., DOM) are the most problemati...

Dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) are generally considered important active biogeochemical pools of total carbon and nitrogen. Many studies have documented the contributions of soil fauna to litter decomposition, but the effects of the soil fauna on labile substances (i.e., DOC and TDN) in litter during early decomposition are not completely clear. Therefore, a f...

a dissolved methane sensor based on silicone tube was designed, constructed and optimized.the silicone tube diameter, silicone tube length and helium flow rate (as the carrier gas(were considered as process parameters to be optimized.a continuous stream of helium (50 ml/min) was directed through the tubing, sweeping out the dissolved methane which diffused through the walls of the tubing from t...

BACKGROUND Succinic acid is a building-block chemical which could be used as the precursor of many industrial products. The dissolved CO2 concentration in the fermentation broth could strongly regulate the metabolic flux of carbon and the activity of phosphoenolpyruvate (PEP) carboxykinase, which are the important committed steps for the biosynthesis of succinic acid by Actinobacillus succinoge...

Hydrogen (H2) is an essential substrate for methanogens to produce methane (CH4), and also influences pathways of volatile fatty acids (VFA) production in the rumen. Dissolved H2 (H2 (aq)) is the form of H2 available to microbes, and dissolved CH4 (CH4 (aq)) is important for indicating methanogens activity. Rumen H2 (aq) concentration has been estimated by assuming equilibrium with headspace ga...

water obtained from any source may contain impurities induced by erosion, dissolved minerals, dissolved gases and material produced from organic matter decomposing. if the amount of these substances exceed a certain limit, not only the water would not be potable, but the water containing the material will not be suitable to be used in most applications, or at least before treatment cannot be ap...

Blood substitutes (modified hemoglobin solutions, perfluorocarbon emulsions) serve as artificial oxygen carriers and are alternatives to blood transfusions. Hemoglobin solutions mimic the sigmoidal oxygen dissociation curve of natural blood. Perfluorocarbon emulsions exhibit a linear relation between PO2 and dissolved oxygen. The most advanced substances may enter medicine in few years.