The Time Interval after Pulsed Irradiation within Which Injury to Bacteria Can Be Modified by Dissolved Oxygen: I. A Search for an Effect of Oxygen 0.02 Second after Pulsed Irradiation

1958 ◽  
Vol 9 (4) ◽  
pp. 422 ◽  
Author(s):  
P. Howard-Flanders ◽  
D. Moore
Keyword(s):  
Dissolved Oxygen ◽  
Time Interval ◽  
Effect Of Oxygen ◽  
Pulsed Irradiation

The effect of oxygen on the concentration of haem in invertebrates

1955 ◽  
Vol 143 (911) ◽  
pp. 203-214 ◽  
Keyword(s):  
Dissolved Oxygen ◽  
Pond Snail ◽  
Blood Haemoglobin ◽  
Tissue Cells ◽  
Effect Of Oxygen ◽  
Haemoglobin Content ◽  
Water Gain

In Daphnia the haemoglobin content of the blood is known to increase in water that is deficient in dissolved oxygen and to decrease in well-aerated water. This is also true of other Cladocera, e.g. Chydorus . Conchostraca in poorly aerated water gain haemoglobin rapidly, but in well-aerated water they lose it slowly; Daphnia gains and loses it at the same rate. Larvae of the dipteran insects Chironomus and Anatopynia , and young of the pond snail Planorbis , synthesize more blood haemoglobin in poorly aerated than in well-aerated water. The annelid worms Arenicola , Scoloplos and Tubifex do not synthesize more blood haemoglobin in poorly aerated water. The haemoglobin content of tissue cells may increase when animals are in poorly aerated water and decrease in well-aerated water. This is so for muscles and nerve ganglia of Daphnia and Conchostraca, but not for muscles of the pond snail Physa or parenchyma of a rhabdocoele worm. Cytochrome in muscles of Daphnia and Conchostraca increases and decreases in amount, just as haemoglobin does, with decrease and increase of environmental oxygen.

scholarly journals Factors affecting the formation and oxidation of sulphides in a polluted estuary

1954 ◽  
Vol 52 (2) ◽  
pp. 194-210 ◽  
Author(s):  
A. B. Wheatland
Keyword(s):  
Surface Layer ◽  
Dissolved Oxygen ◽  
Experimental Work ◽  
Suspended Matter ◽  
Chemical Nature ◽  
Factors Affecting ◽  
Thames Estuary ◽  
Reduction Potentials ◽  
Oxidation Reduction ◽  
Effect Of Oxygen

Factors affecting the formation and destruction of sulphide in the Thames Estuary have been discussed. Measurements of oxidation-reduction potentials show that the effect of oxygen in the water on conditions in deposits of mud is limited to the surface layer. The rate of formation of sulphide increases with temperature, doubling approximately for each 10° C. rise. Reduction of sulphate to sulphide will occur at temperatures as low as 5° C., but even at 25° C. is inhibited by traces of dissolved oxygen. Mud in suspension in the estuary can produce as much sulphide as compact layers of similar mud which might be more anaerobic.Oxidation of sulphide in the Thames Estuary is shown to be of a purely chemical nature; the rate of oxidation, when oxygen is present, is increased by the presence of suspended matter and iron. In the Thames Estuary, however, the rate is limited by the rate at which oxygen enters the water.Much of the experimental work described in this paper was carried out by Miss A. Laird, Mr A. E. Sutton and Mr R. B. Peel of this Laboratory. The paper is published by permission of the Department of Scientific and Industrial Research.

The Effect of Oxygen on the Fluorescence Quenching of Polycyclic Aromatic Hydrocarbons in Two- Component Mixtures of CCl4 with Cyclohexane, Benzene and Acetonitrile

1991 ◽  
Vol 46 (8) ◽  
pp. 707-709 ◽  
Author(s):  
Andrzej Chojnowski ◽  
Wieslaw M. Wiczk ◽  
Tadeusz Latowski
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Fluorescence Quenching ◽  
Dissolved Oxygen ◽  
Aromatic Hydrocarbons ◽  
Fluorescence Lifetimes ◽  
Two Component ◽  
Polycyclic Aromatic ◽  
Effect Of Oxygen

AbstractFluorescence quenching of anthracene and perylene has been studied in deoxygenated and nondeoxygenated two-component mixtures of CCl4 with cyclohexane, benzene and acetonitrile. It was indicate that the dissolved oxygen only reduces the fluorescence lifetimes of the hydrocarbons, thus suppressing the efficiency of quenching

Effect of oxygen-transfer rate on production of L-asparaginase by Erwinia aroideae

1973 ◽  
Vol 19 (9) ◽  
pp. 1153-1158 ◽  
Author(s):  
F. S. Liu ◽  
J. E. Zajic
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Oxygen Transfer Rate ◽  
Oxygen Demand ◽  
Fermentation Medium ◽  
Optimum Level ◽  
Oxygen Requirement ◽  
Asparaginase Activity ◽  
Effect Of Oxygen

A variety of aeration and agitation conditions were used to investigate the oxygen demand of Erwinia aroideae for growth and L-asparaginase production in a 14-liter fermenter. Maximum L-asparaginase activity of 4.25 IU/ml was obtained when the fermentation medium was aerated at 0.5 volumes air per volume medium per minute and agitated at 500 rpm. However, the specific L-asparaginase activity was not affected significantly by the rate of oxygen transfer. In most instances the level of dissolved oxygen decreased to zero before harvesting. KLa rather than dissolved oxygen as measured during the fermentation cycle is a more satisfactory index to determine the oxygen requirement for cell growth and asparaginase production. The optimum level of KLa for L-asparaginase production was 0.98 min−1. However, a higher value of KLa of 1.2–1.9 min−1 was needed to achieve the highest growth.

scholarly journals The effect of dissolved oxygen on microgreen productivity

2021 ◽  
Vol 30 ◽  
pp. 05002
Author(s):  
Alexander Grishin ◽  
Andrey Grishin ◽  
Natalia Semenova ◽  
Vladimir Grishin ◽  
Inna Knyazeva ◽  
...  
Keyword(s):  
Weight Loss ◽  
Seed Germination ◽  
Species Composition ◽  
Dissolved Oxygen ◽  
Oxygen Saturation ◽  
Dry Weight ◽  
Multicomponent Mixtures ◽  
Plant Parts ◽  
Wet Weight ◽  
Effect Of Oxygen

The effect of oxygen dissolved in water was researched (1.3 mg/l – without saturation, 6.1 mg/l – air saturation, 14.7 mg/l – oxygen saturation) on the microgreen productivity of “Ivolga” variety wheat of and ‘Aida’ variety lentils. It was found that the enrichment of water for seed germination with oxygen stimulates the speedy germination and receipt of wheat and lentils sprouts 1 day faster than in the variant without saturation. An increase in oxygen concentration contributes to the rapid root system growth of the researched cultures, stimulates the formation of 2 order roots, accelerates the development of the overhead plant parts without dry weight loss. On the 7th day of cultivation, the wet weight of wheat increased by 21% in the variant with air saturation and 56% with oxygen saturation, wet weight of lentils – by 57% and 77%, respectively. Both a deficiency and an excess of oxygen in water can adversely affect the content of basic pigments. Therefore, it is necessary to select the species composition of cultures for composing multicomponent mixtures, to obtain higher microgreen quality when grown on oxygen-rich solutions.

Long-term variability of oceanographic data at the Port Hacking 50-metre station

1977 ◽  
Vol 28 (1) ◽  
pp. 57 ◽  
Author(s):  
SD Hahn ◽  
DJ Rochford ◽  
JS Godfrey
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Inorganic Phosphate ◽  
Time Interval ◽  
Seasonal Cycles ◽  
Oceanographic Variables ◽  
Oceanographic Data ◽  
Annual Means

Measurements of water temperature, salinity, dissolved oxygen, nitrate and inorganic phosphate have been made at the Port Hacking 50-m station which is about 30 km south of Sydney and 5 km offshore. This paper reports an analysis of the data obtained between 1942 and 1972. Mean seasonal cycles of each of these variables have been evaluated for the time interval, as well as the annual means for each year. Shorter period fluctuations are studied by cross correlating the monthly anomalies of the various oceanographic variables.

Effect of Oxygen Concentration in Static Pb-Bi Eutectic on Corrosion Mode of Aluminum-Alloyed Austenitic Steels at 550 °C for 1000 h

2021 ◽  
Vol 1024 ◽  
pp. 79-85
Author(s):  
Valentyn Tsisar ◽  
Zhang Jian Zhou ◽  
Olaf Wedemeyer ◽  
Aleksandr Skrypnik ◽  
Carsten Schroer
Keyword(s):  
Liquid Metal ◽  
Oxide Film ◽  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Corrosion Behavior ◽  
Austenitic Steels ◽  
Ferrite Layer ◽  
Effect Of Oxygen ◽  
Corrosion Mode ◽  
Al Oxide

Corrosion behavior of Fe-18Ni-12Cr-2.30Al and Fe-18Ni-12Cr-2.90Al-Nb-C austenitic steels was investigated in static Pb-Bi eutectic at 550 °C for 1000 h depending on the concentration of dissolved oxygen in the liquid metal. In the concentration range from 1012 to 108 mass % O, both steels underwent corrosion via dissolution resulted in the formation of spongy ferrite layer depleted in Ni and Cr and penetrated by Pb and Bi. In Pb-Bi with 106 mass % O, Fe-18Ni-12Cr-2.90Al-Nb-C steel oxidizes with formation of very thin (≤ 1 μm) Cr/Al oxide film while Fe-18Ni-12Cr-2.30Al steel shows mixed corrosion behavior represented by more intensive oxidation and dissolution. The features of corrosion response are discussed depending on the composition of steels and concentration of dissolved oxygen in the Pb-Bi eutectic.

A TEM study of the effect of oxygen on nanocavity formation and precipitation in rapid - solidified Fe-16Ni-9Cr stainless steels

1994 ◽  
Vol 52 ◽  
pp. 700-701
Author(s):  
S. Wisutmethangoon ◽  
T. F. Kelly ◽  
J.E. Flinn
Keyword(s):  
Stainless Steels ◽  
High Mobility ◽  
Hot Extrusion ◽  
Extrusion Ratio ◽  
Gas Atomization ◽  
Cavity Formation ◽  
Nucleation Sites ◽  
Heat Treated ◽  
Different Types ◽  
Effect Of Oxygen

Vacancies are introduced into the crystal phase during quenching of rapid solidified materials. Cavity formation occurs because of the coalescence of the vacancies into a cluster. However, because of the high mobility of vacancies at high temperature, most of them will diffuse back into the liquid phase, and some will be lost to defects such as dislocations. Oxygen is known to stabilize cavities by decreasing the surface energy through a chemisorption process. These stabilized cavities, furthermore, act as effective nucleation sites for precipitates to form during aging. Four different types of powders with different oxygen contents were prepared by gas atomization processing. The atomized powders were then consolidated by hot extrusion at 900 °C with an extrusion ratio 10,5:1. After consolidation, specimens were heat treated at 1000 °C for 1 hr followed by water quenching. Finally, the specimens were aged at 600 °C for about 800 hrs. TEM samples were prepared from the gripends of tensile specimens of both unaged and aged alloys.

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