scholarly journals Effects of Three Types of Oil Dispersants on Biodegradation of Dispersed Crude Oil in Water Surrounding Two Persian Gulf Provinces

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Azadeh Zolfaghari-Baghbaderani ◽  
Mozhgan Emtyazjoo ◽  
Parinaz Poursafa ◽  
Sedigheh Mehrabian ◽  
Samira Bijani ◽  
...  
Keyword(s):  
Growth Rate ◽  
Persian Gulf ◽  
Culture Medium ◽  
Oxygen Demand ◽  
Maximum Amount ◽  
Oil Dispersants ◽  
Oil In Water ◽  
Bacteria And Fungi ◽  
Spilled Oil ◽  
Secondary Contamination

Objective. To determine the most effective and biodegradable dispersant of spilled oil in water surrounding two Persian Gulf provinces.Methods. This study compared the effects of three dispersants, Pars 1, Pars 2, and Gamlen OD4000 on removal of oil in two Persian Gulf provinces' water. Overall, 16 stations were selected. Using the Well method, the growth rate of isolated bacteria and fungi was identified. To specify the growth rate of microorganisms and their usage of oil in the presence of the above-mentioned dispersants, as exclusive sources of carbon, the bacteria were grown in culture medium for 28 days at 120 rpm,30∘C, and their optical density was measured by spectrophotometry. Then, we tested biological oxygen demand (BOD) and chemical oxygen demand (COD) in microorganisms.Results. The highest growth rate was documented for the growth of microorganisms on either Pars 1 or Pars 2 dispersants or their mixtures with oil. However, the culture having microorganisms grown on Pars 1 had higher BOD and COD than the other two dispersants (9200 and 16800 versus 500 and 960,P<0.05). Mixture of oil and Pars 2 as well as oil and Pars 1 dispersants showed the highest BODs and CODs, respectively. In the Bahregan province, microorganisms grown on Pars 2 had maximum amount of BOD and COD in comparison with Pars 1 and Gamlen dispersants (7100 and 15200 versus 6000 and 10560,P<0.05).Conclusion. Pars 1 and Pars 2 were the most effective dispersants with highest degradability comparing Gamlen. In each region, the most suitable compound for removing oil spill from offshores with least secondary contamination should be investigated.

scholarly journals Effects of cofD gene knock-out on the methanogenesis of Methanobrevibacter ruminantium

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jian Ma ◽  
Xueying Wang ◽  
Ting Zhou ◽  
Rui Hu ◽  
Huawei Zou ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Production Capacity ◽  
Maximum Amount ◽  
Logarithmic Phase ◽  
Wild Type ◽  
Knock Out ◽  
Maximum Biomass ◽  
Reproductive Ability ◽  
Methanobrevibacter Ruminantium

AbstractThis study aimed to investigate the effects of cofD gene knock-out on the synthesis of coenzyme F420 and production of methane in Methanobrevibacter ruminantium (M. ruminantium). The experiment successfully constructed a cofD gene knock-out M. ruminantium via homologous recombination technology. The results showed that the logarithmic phase of mutant M. ruminantium (12 h) was lower than the wild-type (24 h). The maximum biomass and specific growth rate of mutant M. ruminantium were significantly lower (P < 0.05) than those of wild-type, and the maximum biomass of mutant M. ruminantium was approximately half of the wild-type; meanwhile, the proliferation was reduced. The synthesis amount of coenzyme F420 of M. ruminantium was significantly decreased (P < 0.05) after the cofD gene knock-out. Moreover, the maximum amount of H2 consumed and CH4 produced by mutant were 14 and 2% of wild-type M. ruminantium respectively. In conclusion, cofD gene knock-out induced the decreased growth rate and reproductive ability of M. ruminantium. Subsequently, the synthesis of coenzyme F420 was decreased. Ultimately, the production capacity of CH4 in M. ruminantium was reduced. Our research provides evidence that cofD gene plays an indispensable role in the regulation of coenzyme F420 synthesis and CH4 production in M. ruminantium.

scholarly journals Visual Appearance of Oil on the Sea

2021 ◽  
Vol 9 (1) ◽  
pp. 97
Author(s):  
Merv Fingas
Keyword(s):  
Water Surface ◽  
Oil Spills ◽  
Discharge Rate ◽  
Physical Explanation ◽  
Visual Appearance ◽  
Oil In Water ◽  
Other Information ◽  
Surface Discharges ◽  
Oil Emulsions ◽  
Spilled Oil

The visual appearance of oil spills at sea is often used as an indicator of spilled oil properties, state and slick thickness. These appearances and the oil properties that are associated with them are reviewed in this paper. The appearance of oil spills is an estimator of thickness of thin oil slicks, thinner than a rainbow sheen (<3 µm). Rainbow sheens have a strong physical explanation. Thicker oil slicks (e.g., >3 µm) are not correlated with a given oil appearance. At one time, the appearance of surface discharges from ships was thought to be correlated with discharge rate and vessel speed; however, this approach is now known to be incorrect. Oil on the sea can sometimes form water-in-oil emulsions, dependent on the properties of the oil, and these are often reddish in color. These can be detected visually, providing useful information on the state of the oil. Oil-in-water emulsions can be seen as a coffee-colored cloud below the water surface. Other information gleaned from the oil appearance includes coverage and distribution on the surface.

scholarly journals Optimal Strategies for Prudent Investors

1998 ◽  
Vol 01 (04) ◽  
pp. 473-486 ◽  
Author(s):  
Roberto Baviera ◽  
Michele Pasquini ◽  
Maurizio Serva ◽  
Angelo Vulpiani
Keyword(s):  
Growth Rate ◽  
Random Walk ◽  
Exponential Growth ◽  
Optimal Strategies ◽  
Maximum Amount ◽  
Exponential Growth Rate ◽  
One Dimensional ◽  
Economic Level ◽  
Random Walk With Drift ◽  
Analytical Expressions

We consider a stochastic model of investment on an asset in a stock market for a prudent investor. she decides to buy permanent goods with a fraction α of the maximum amount of money owned in her life in order that her economic level never decreases. The optimal strategy is obtained by maximizing the exponential growth rate for a fixed α. We derive analytical expressions for the typical exponential growth rate of the capital and its fluctuations by solving an one-dimensional random walk with drift.

scholarly journals Oil Dispersants Deadly to a Common Estuary Species

Eos ◽  
2015 ◽  
Vol 96 ◽  
Author(s):  
Brendan Bane
Keyword(s):  
Oil Dispersants ◽  
Salty Water ◽  
Break Up ◽  
Spilled Oil

Research on two dispersants used to break up spilled oil suggests that the chemicals can kill or harm a widely–found shrimp important to estuary habitats. The toxicity increases in less salty water.

scholarly journals Selection of the optimal culture medium for cultivation Fusarium sporotrichioides Sherb

2020 ◽  
Author(s):  
I.L. Astapchuk ◽  
◽  
N.A. Marchenko ◽  
G.V. Yakuba ◽  
A.I. Nasonov ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth And Development ◽  
Maximum Degree ◽  
Culture Medium ◽  
Culture Media ◽  
High Variability ◽  
Fusarium Sporotrichioides ◽  
Cultural Characteristics ◽  
Colony Diameter ◽  
Selection Of

The influence of various culture media on the growth, morphological and cultural characteristics of the fungus F. sporotrichioides was studied. Ten culture media were used in our research. A comparative study of the growth rate of the F. sporotrichioides mycelium made it possible to identify two media that are the most suitable for the cultivation and identification of this species, namely carrot and tomato agar. We took into account such criteria as ensuring the maximum degree of sporulation, rapid growth and development of mycelium (the 7th day), colony diameter (71–78 mm), as well as the ease of preparation. Nirenberg culture medium can be used to obtain a large number of conidia of the fungus. Because of the high variability of cultural characteristics of F. sporotrichioides, we recommend using different composition of media.

Effects Of Aspirin And Sulfinpyrazone On Platelets, Vascular Cells And Their Interactions

1981 ◽  
Author(s):  
M R Buchanan ◽  
M J Vazquez ◽  
M A Gimbrone
Keyword(s):  
Growth Rate ◽  
Cell Growth ◽  
Dna Synthesis ◽  
Vessel Wall ◽  
Culture Medium ◽  
Platelet Adhesion ◽  
Thymidine Incorporation ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Final Density

Sulfinpyrazone (SUL) and aspirin (ASA) are potentially useful antithrombotic drugs. Both drugs are thought to exert this effect by inhibiting the platelet enzyme, cyclooxygenase (C-0), thus preventing thromboxane A2 synthesis. Recent data, however, suggest that these drugs also may affect vessel wall cells. To study this further, we examined the effects of SUL and ASA on i) the adhesion of 3H-adenine-labelled washed human platelets to cultured bovine endothelial (EC) and smooth muscle cells (SMC), ii) EC and SMC DNA synthesis (3H-thymidine incorporation) and iii) cell growth. Pretreatment of platelets with 100μM ASA or 250μM SUL (concentrations sufficient to inhibit C-0), did not affect platelet adhesion to untreated EC or SMC. However, adhesion of untreated, ASA- and SUL-platelets was increased 25,28 and 44% resp. when EC were pretreated with 650μM SUL for 24 hr. In contrast, adhesion of ASA-platelets to EC pretreated with lOOμM ASA (sufficient to inhibit prostacyclin), was unaffected. Platelet adhesion to SMC pretreated with 650μM SUL for 24 hr was decreased when platelets also were pretreated with ASA (20%, p<0.05) or SUL (27%, pc 0.02). Pretreatment of SMC with SUL for only 2 hr had no effect. DNA synthesis in EC and SMC treated with 62.5 and 250μM SUL for 24 hr, was inhibited >35% and >95% resp. Preliminary data suggest that this inhibitory effect may last longer in SMC. To study the effect of SUL on cell growth, EC and SMC were plated at 2 × 104 cells/ cm2 and fed with culture medium containing 0, 62.5 or 625uM SUL on day 0, 1, 3 and 4.5. EC growth rate and final density were unaffected over 7 days. SMC growth rate also was unaffected, but the final density of SMC treated with 650μM SUL was 31 μ 2% less than untreated SMC at 7 days (p<0.01). These data indicate that SUL has direct effects on EC and SMC that may influence i) platelet-vessel wall interactions and ii) vascular cell proliferation.

scholarly journals Psychiatry in Iran

2005 ◽  
Vol 2 (10) ◽  
pp. 10-12 ◽  
Author(s):  
Majid Sadeghi ◽  
Gholamreza Mirsepassi
Keyword(s):  
Growth Rate ◽  
Rural Areas ◽  
Persian Gulf ◽  
Population Growth Rate ◽  
Total Population ◽  
Islamic Republic ◽  
Land Area ◽  
The Caspian Sea ◽  
Islamic Republic Of Iran ◽  
The Persian Gulf

The Islamic Republic of Iran is located in the Middle East between the Caspian Sea and the Persian Gulf. Iran's total land area is 1 648 000 km2. Its total population in 2003 was about 68 920 000 (UNICEF, 2003). The population growth rate is 1.41%. Of the total population, 60.4% live in urban and 39.6% in rural areas (Yasamy et al, 2001).

STUDY ON THE BIODEGRADATION OF OIL SPILLED ON THE SEA

1997 ◽  
Vol 1997 (1) ◽  
pp. 989-990 ◽  
Author(s):  
Zhao Jianqiang ◽  
Zhu Junhuang
Keyword(s):  
Chemical Composition ◽  
Dissolved Oxygen ◽  
Oxygen Content ◽  
Oxygen Demand ◽  
Nutrient Elements ◽  
Factors Affecting ◽  
Major Factors ◽  
Spilled Oil

ABSTRACT Three major factors affecting the biodegradation of spilled oil (chemical composition of spilled oil, dissolved oxygen content in water, and nutrient elements for microorganisms) were analysed. The sequences of biodegradation rates of some hydrocarbon compounds are summarized. The oxygen demand for biodegradation of 1 g of hydrocarbons was derived as 3 to 4 g. The maximum ratio of carbon (C), nitrogen (N), and phosphorus (P) that microorganisms need was suggested as C:N:P = 100:7:0.14.

The Effects of Alkaline Treatment on Excess Sludge Supernatant Characteristics

2013 ◽  
Vol 361-363 ◽  
pp. 1046-1049 ◽  
Author(s):  
Ting Ting Li ◽  
Zhi Min Fu
Keyword(s):  
Ph Value ◽  
Sodium Hydroxide Solution ◽  
Alkali Treatment ◽  
Oxygen Demand ◽  
Alkaline Treatment ◽  
Maximum Amount ◽  
Batch Experiments ◽  
Excess Sludge ◽  
Initial Ph ◽  
Soluble Chemical Oxygen Demand

The effect of alkali treatment on excess sludge supernatant characteristics was studied in this experiment. 4 mol/L sodium hydroxide solution was utilized to adjust the initial pH value of excess sludge to 9.0, 11.0 and 13.0. Batch experiments were operated in 35 °C shaking bath for 12 h. The soluble chemical oxygen demand (SCOD), protein and polysaccharide concentration in excess sludge supernatant was measured every 3 h. The experimental results showed that maximum amount of protein, polysaccharide and SCOD were obtained when the initial pH value was 13.0.

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