The photodegradation of metronidazole in the presence of coexisting pharmaceuticals

2012 ◽  
Vol 66 (4) ◽  
pp. 735-740 ◽  
Author(s):  
Bo Wu ◽  
Ting Zhang ◽  
Jinxia Li ◽  
Yong Ye ◽  
Huaixia Chen
Keyword(s):  
Surface Water ◽  
Absorption Spectra ◽  
Environmental Water ◽  
Ultraviolet Absorption ◽  
Solar Irradiation ◽  
Batch Experiments ◽  
The Relationship

The objective of this study was to investigate if coexisting compounds could affect the fate of pharmaceuticals in surface water under solar irradiation. The degradation of metronidazole (MET) in the presence of different coexisting pharmaceuticals was investigated in batch experiments with exposure to sunlight. Tinidazole, which has a similar structure to MET, was employed as an analogue. The results indicated that the presence of an analogue with a similar photosensitive group to MET could inhibit the photodegradation of MET. In addition, the effect of coexisting pharmaceuticals with different absorption spectra on the degradation of MET was investigated. The results showed that the effect depended on the degree of overlapping absorption spectra between MET and the coexisting pharmaceuticals. The relationship between the degree of the influence and the ultraviolet absorption spectra of coexisting pharmaceuticals found in this study could give guidance in assessing the fate of pharmaceuticals in environmental water.

Environmental Water Stress in Transboundary River Basins

2017 ◽  
Author(s):  
Tales Carvalho-Resende
Keyword(s):  
Water Stress ◽  
Surface Water ◽  
Environmental Water ◽  
River Basins ◽  
Water Quantity ◽  
Natural Flow Regime ◽  
Transboundary River ◽  
Transboundary River Basins ◽  
Natural Flow ◽  
Water Uses

The Environmental Water Stress in Transboundary River Basins indicator focuses on the water quantity aspect and considers hydrological alterations from monthly dynamics of the natural flow regime due to anthropogenic water uses and dam operations. For more information, visit: http://twap-rivers.org/ Basin Stress Surface water Transboundary

Changing Places: Rock Art and Holocene Landscapes in the Wadi al-Ajal, South-West Libya

2014 ◽  
Vol 12 (2) ◽  
pp. 165-182 ◽  
Author(s):  
Tertia Barnett ◽  
Maria Guagnin
Keyword(s):  
Spatial Analysis ◽  
Surface Water ◽  
Rock Art ◽  
Human Settlement ◽  
Gis Model ◽  
South West ◽  
Settlement Location ◽  
Central Sahara ◽  
The Relationship ◽  
Over Time

This article examines the relationship between rock art and landscape use by pastoral groups and early settled communities in the central Sahara from around 6000 BC to 1000 AD. During this period the region experienced significant climatic and environmental fluctuations. Using new results from a systematic survey in the Wadi al-Ajal, south-west Libya, our research combines data from over 2000 engraved rock art panels with local archaeological and palaeoenvironmental evidence within a GIS model. Spatial analysis of these data indicates a correspondence between the frequency of rock art sites and human settlement over time. However, while changes in settlement location were guided primarily by the constraints on accessibility imposed by surface water, the distribution of rock art relates to the availability of pasture and patterns of movement through the landscape. Although the reasons for these movements undoubtedly altered over time, natural routes that connected the Wadi al-Ajal and areas to the south continued to be a focus for carvings over several thousand years.

FAR ULTRAVIOLET ABSORPTION SPECTRA OF N3AND N2+GENERATED BY ELECTRONS IMPACTING GASEOUS N2

2013 ◽  
Vol 779 (1) ◽  
pp. 40 ◽  
Author(s):  
Yu-Jong Wu ◽  
Hui-Fen Chen ◽  
Shiang-Jiun Chuang ◽  
Tzu-Ping Huang
Keyword(s):  
Absorption Spectra ◽  
Ultraviolet Absorption ◽  
Far Ultraviolet

scholarly journals ULTRAVIOLET ABSORPTION SPECTRA AT REDUCED TEMPERATURES

1950 ◽  
Vol 187 (1) ◽  
pp. 299-312
Author(s):  
R.L. Sinsheimer ◽  
J.F. Scott ◽  
J.R. Loofbourow
Keyword(s):  
Absorption Spectra ◽  
Ultraviolet Absorption

ULTRAVIOLET ABSORPTION SPECTRA AND ACIDITIES OF ISOMERIC THIATRIAZOLE AND TETRAZOLE DERIVATIVES

1959 ◽  
Vol 37 (3) ◽  
pp. 563-574 ◽  
Author(s):  
Eugene Lieber ◽  
J. Ramachandran ◽  
C. N. R. Rao ◽  
C. N. Pillai
Keyword(s):  
Absorption Spectra ◽  
Absorption Maximum ◽  
Dipole Moments ◽  
Ring System ◽  
Ultraviolet Absorption ◽  
Characteristic Absorption ◽  
Tetrazole Derivatives

The ultraviolet absorption spectra of 5-(substituted)amino-1,2,3,4-thiatriazoles and the corresponding isomeric 1-substituted-tetrazoline-5-thiones have been studied. The spectra and the dipole moments of the 5-(substituted)amino-1,2,3,4-thiatriazoles eliminate the possibility of meso-ionic structures for these compounds. The dipole moments of 5-amino-, 5-methylamino-, and 5-dimethylamino-1,2,3,4-thiatriazole were all high but approximately of the same value (5.77 to 5.84 D). This suggests that the amino thiatriazoles are best represented by conventional covalent structures with significant ionic resonance contributions. The thiatriazole ring system exhibits a characteristic absorption maximum at 250–255 mμ and an electron-withdrawing effect approximately equal to the tetrazolyl ring system. The tetrazolinethionolyl ring system is similarly electron-withdrawing. The relative acidities of the 1-substituted-tetrazoline-5-thiones and the 5-alkylmercaptotetrazoles have also been studied and the results support the observations made on the basis of their ultraviolet absorption spectra.

Sign in / Sign up

Export Citation Format

Share Document