Cycloreversion performance of coumarin and hetero-coumarin dimers under aerobic conditions: unexpected behavior triggered by UV-A light

2021 ◽  
Author(s):  
Nikolai Bieniek ◽  
Sebastian Inacker ◽  
Norbert Hampp
Keyword(s):  
Aerobic Conditions ◽  
Cleavage Reactions ◽  
Photo Cleavage ◽  
Unexpected Behavior

Photochemical [2+2]-cycloadditions of coumarin-like monomers are the textbook paradigms of photo-formation and photo-cleavage reactions.

The Reaction of Thiol Compounds with the Vitamin-K Dependent Clotting Factors

1969 ◽  
Vol 21 (03) ◽  
pp. 573-579 ◽  
Author(s):  
P Fantl
Keyword(s):  
Prothrombin Time ◽  
Vitamin K ◽  
Anaerobic Conditions ◽  
Clotting Factors ◽  
Thiol Compounds ◽  
Aerobic Conditions ◽  
One Stage ◽  
Factor Ii ◽  
Ph Dependent ◽  
The One

SummaryTreatment of human and dog oxalated plasma with 0.2 to 1.0 × 10−1 M 2.3-dithiopropanol (BAL) or dithiothreitol (DTT) at 2–4° C for 30 min results in the reduction of the vitamin-K dependent clotting factors II, VII, IX and X to the respective-SH derivatives. The reaction is pH dependent. Under aerobic conditions the delayed one stage prothrombin time can be partly reversed. Under anaerobic conditions a gradual prolongation of the one stage prothrombin time occurs without reversal.In very diluted plasma treated with the dithiols, prothrombin can be converted into thrombin if serum as source of active factors VII and X is added. In contrast SH factors VII, IX and X are inactive in the specific tests. Reoxidation to active factors II, VII, IX and X takes place during adsorption and elution of the SH derivatives. The experiments have indicated that not only factor II but also factors VII, IX and X have active-S-S-centres.

Photoinduced N-Demethylation of Rufloxacin and its Methyl Ester Under Aerobic Conditions¶

2002 ◽  
Vol 76 (3) ◽  
pp. 252 ◽  
Author(s):  
Alessandra Belvedere ◽  
Francisco Boscá ◽  
M. Consuelo Cuquerella ◽  
Guido de Guidi ◽  
Miguel A. Miranda
Keyword(s):  
Methyl Ester ◽  
Aerobic Conditions

Pond Treatment of Rettery Wastewaters

1987 ◽  
Vol 19 (12) ◽  
pp. 79-83
Author(s):  
K. Bartoszewski ◽  
A. Bilyk
Keyword(s):  
Activated Sludge ◽  
Treatment Process ◽  
New Technology ◽  
Treatment Plant ◽  
Anaerobic Treatment ◽  
Cod Removal ◽  
Experimental Results ◽  
Aerobic Conditions ◽  
Aerobic Stabilization ◽  
In Series

Rettery wastewaters were treated in anaerobic and aerobic ponds. Anaerobic treatment yielded efficiencies of BOD5 and COD removal as low as 20%. The treatment process conducted under aerobic conditions in aerated and stabilizing ponds arranged in series took from 18 to 20 days and gave efficiencies of BOD5 and COD removal amounting to 90%. The experimental results were interpreted by virtue of the Eckenfelder equation. Excess activated sludge was subjected to aerobic stabilization in a separate tank. A new technology was suggested for the existing obsolete industrial treatment plant.

Ammonia removal in a pilot-scale WSP complex in Northeast Brazil

1996 ◽  
Vol 33 (7) ◽  
pp. 165-171 ◽  
Author(s):  
J. Soares ◽  
S. A. Silva ◽  
R. de Oliveira ◽  
A. L. C. Araujo ◽  
D. D. Mara ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Surface Waters ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Ammonia Removal ◽  
Northeast Brazil ◽  
Environmental Legislation ◽  
Aerobic Conditions ◽  
High Degree

Ammonia removal was monitored in a waste stabilisation pond complex comprising ponds of different geometries and depths under two different operational regimes. It was found that a high degree of ammonia removal commenced in the secondary maturation ponds, with the highest removals occurring in the shallowest ponds as a consequence of improved aerobic conditions. The tertiary maturation ponds produced effluents with mean ammonia concentrations of < 5 mg N/l, the maximum permitted recommended by Brazilian environmental legislation for the discharge of effluents of wastewater treatment plants into surface waters. Ammonia removal in the secondary facultative and maturation ponds could be modelled using equations based on the volatilization mechanism proposed by Middlebrooks et al. (1982).

Hydrolysis of organic wastewater particles in laboratory scale and pilot scale biofilm reactors under anoxic and aerobic conditions

1998 ◽  
Vol 38 (8-9) ◽  
pp. 179-188 ◽  
Author(s):  
K. F. Janning ◽  
X. Le Tallec ◽  
P. Harremoës
Keyword(s):  
Organic Matter ◽  
Mass Balance ◽  
Particulate Organic Matter ◽  
Removal Rate ◽  
Pilot Scale ◽  
Laboratory Scale ◽  
Synthetic Wastewater ◽  
Aerobic Conditions ◽  
Biofilm Reactors ◽  
Hydrolysis Of

Hydrolysis and degradation of particulate organic matter has been isolated and investigated in laboratory scale and pilot scale biofilters. Wastewater was supplied to biofilm reactors in order to accumulate particulates from wastewater in the filter. When synthetic wastewater with no organic matter was supplied to the reactors, hydrolysis of the particulates was the only process occurring. Results from the laboratory scale experiments under aerobic conditions with pre-settled wastewater show that the initial removal rate is high: rV, O2 = 2.1 kg O2/(m3 d) though fast declining towards a much slower rate. A mass balance of carbon (TOC/TIC) shows that only 10% of the accumulated TOC was transformed to TIC during the 12 hour long experiment. The pilot scale hydrolysis experiment was performed in a new type of biofilm reactor - the B2A® biofilter that is characterised by a series of decreasing sized granular media (80-2.5 mm). When hydrolysis experiments were performed on the anoxic pilot biofilter with pre-screened wastewater particulates as carbon source, a rapid (rV, NO3=0.7 kg NO3-N/(m3 d)) and a slowler (rV, NO3 = 0.3 kg NO3-N/(m3 d)) removal rate were observed at an oxygen concentration of 3.5 mg O2/l. It was found that the pilot biofilter could retain significant amounts of particulate organic matter, reducing the porosity of the filter media of an average from 0.35 to 0.11. A mass balance of carbon shows that up to 40% of the total incoming TOC accumulates in the filter at high flow rates. Only up to 15% of the accumulated TOC was transformed to TIC during the 24 hour long experiment.

Hydrogenation-dehydrogenation and cleavage functions of hydrorefining catalysts studied by the reaction of tetrahydrothiophene

1986 ◽  
Vol 51 (12) ◽  
pp. 2770-2780 ◽  
Author(s):  
Alexandra Drahorádová ◽  
Miroslav Zdražil
Keyword(s):  
Activated Carbon ◽  
Catalyst Surface ◽  
Bond Cleavage ◽  
Unsaturated Hydrocarbons ◽  
Cleavage Reactions

The reaction of tetrahydrothiophene in a stream of nitrogen was used to study the relations between dehydrogenation and C-S cleavage reactions on sulphided Co-Mo/Al2O3 catalysts. The course of the reaction was compared for Co-Mo catalysts supported on alumina and activated carbon, for alumina alone as well as for a Pt/C catalyst. The effect of substitution of nitrogen for hydrogen, of the addition of water to the feed, of pre-sulphidation of catalysts and their deactivation by coking on the rate and selectivity of the reaction were also investigated. The results showed that hydrogenation-dehydrogenation and dehydrosulphurization activity of the sulphide catalysts have the same origin. Hydrogen accelerates dehydrosulphurization on the sulphide catalysts by removing sulphur and unsaturated hydrocarbons formed on catalyst surface by C-S bond cleavage reactions.

Cleavage of the Epimines of 1,6-Anhydrohexoses with Fluoride Anion

2005 ◽  
Vol 70 (12) ◽  
pp. 2075-2085 ◽  
Author(s):  
Jiří Kroutil ◽  
Klára Jeništová
Keyword(s):  
Fluoride Anion ◽  
Ring Cleavage ◽  
Protecting Group ◽  
Reaction Conditions ◽  
Aziridine Ring ◽  
Cleavage Reactions ◽  
Derivatives Of ◽  
Fluoro Derivatives

Aziridine ring cleavage reactions of five N-nosylepimines (2-6) having D-talo, D-galacto, D-manno, and D-allo configurations with potassium hydrogendifluoride under various reaction conditions have been performed. The cleavage regioselectively afforded diaxial isomers of vicinal amino-fluoro derivatives of 1,6-anhydro-β-D-gluco- and mannopyranose 7-11 in 51-94% yields. Removal of 2-nitrobenzenesulfonyl protecting group with benzenethiol has been attempted in the case of compound 10.

scholarly journals A novel high-content screening approach for the elucidation of C. jejuni biofilm composition and integrity

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Matthew V. X. Whelan ◽  
Jeremy C. Simpson ◽  
Tadhg Ó Cróinín
Keyword(s):  
Atmospheric Oxygen ◽  
Chicken Meat ◽  
Live Cells ◽  
High Throughput Analysis ◽  
Aerobic Conditions ◽  
Poultry Products ◽  
Source Of Infection ◽  
Fluorescent Markers ◽  
Oxygen Conditions ◽  
Bacterial Gastroenteritis

Abstract Background Campylobacter jejuni is the leading cause of bacterial gastroenteritis worldwide and the main source of infection is contaminated chicken meat. Although this important human pathogen is an obligate microaerophile, it must survive atmospheric oxygen conditions to allow transmission from contaminated chicken meat to humans. It is becoming increasingly evident that formation of biofilm plays a key role in the survival of this organism for extended periods on poultry products. We have recently demonstrated a novel inducible model for the study of adherent C. jejuni biofilm formation under aerobic conditions. By taking advantage of supercoiling mediated gene regulation, incubation of C. jejuni with subinhibitory concentrations of the Gyrase B inhibitor novobiocin was shown to promote the consistent formation of metabolically active adherent biofilm. Results In this study, we implement this model in conjunction with the fluorescent markers: TAMRA (live cells) and SytoX (dead cells, eDNA) to develop a novel systematic high-content imaging approach and describe how it can be implemented to gain quantifiable information about the integrity and extracellular polymeric substance (EPS) composition of adherent C. jejuni biofilm in aerobic conditions. We show that this produces a model with a consistent, homogenous biofilm that can be induced and used to screen a range of inhibitors of biofilm adherence and matrix formation. Conclusions This model allows for the first time a high throughput analysis of C. jejuni biofilms which will be invaluable in enabling researchers to develop mechanisms to disrupt these biofilms and reduce the viability of these bacteria under aerobic conditions.

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