Repeated use of two Chlorella species, C. vulgaris and WW1 for cyclic nickel biosorption

The activity of ruthenium, palladium, and nickel catalysts for the hydrogenation of 1,2-dihydroacenaphthylene in cyclohexane solution was studied at temperatures up to 180 °C and pressures up to 8 MPa. The GC-MS technique was used to identify most of the perhydroacenaphthylene stereoisomers, whose fractions in the product were found dependent on the nature of the active component of the catalyst. The hydrogenation was fastest on the palladium catalyst (3% Pd/C). The nickel catalyst Ni-NiO/Al2O3, which is sufficiently active also after repeated use, can be recommended for practical application. The activation energy of 1,2-dihydroacenaphthylene hydrogenation using this catalyst is 17 kJ/mol, the reaction order with respect to hydrogen is unity.

Download Full-text

Australia and People Seeking Asylum who Arrive by Boat

The Oxford Handbook of Migration Crises ◽

10.1093/oxfordhb/9780190856908.013.55 ◽

2018 ◽

pp. 518-536

Author(s):

Caroline Fleay

Keyword(s):

Political Parties ◽

United Nations ◽

Government Policies ◽

The Past ◽

The People ◽

The Status ◽

Repeated Use ◽

United Nations Convention ◽

The United Nations

Throughout the past forty years various leaders from both major political parties in Australia have categorized the arrival by boat of people seeking asylum as a “crisis” and the people themselves as “illegal.” This is despite Australia being a signatory to the United Nations Convention Relating to the Status of Refugees, and receiving relatively few people who seek asylum compared with many other countries. Punitive government policies and processes have further reinforced these representations, such that “crisis” and “illegal” can now be understood as both categories of analysis and practice. The repeated use of such categories may be helping to produce and reproduce prejudice and racism and obscure the needs and experiences of people seeking asylum.

Download Full-text

Promising Immobilization of Industrial-Class Phospholipase A1 to Attain High-Yield Phospholipids Hydrolysis and Repeated Use with Optimal Water Content in Water-in-Oil Microemulsion Phase

Applied Sciences ◽

10.3390/app11041456 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1456

Author(s):

Yusuke Hayakawa ◽

Ryoichi Nakayama ◽

Norikazu Namiki ◽

Masanao Imai

Keyword(s):

Water Content ◽

Reaction Rate ◽

Enzyme Reaction ◽

Initial Reaction Rate ◽

Industrial Applications ◽

Molar Ratio ◽

High Yield ◽

Initial Reaction ◽

Phospholipase A1 ◽

Repeated Use

In this study, we maximized the reactivity of phospholipids hydrolysis with immobilized industrial-class phospholipase A1 (PLA1) at the desired water content in the water-in-oil (W/O) microemulsion phase. The optimal hydrophobic-hydrophilic condition of the reaction media in a hydrophobic enzyme reaction is critical to realize the maximum yields of enzyme activity of phospholipase A1. It was attributed to enzymes disliking hydrophobic surroundings as a special molecular structure for reactivity. Immobilization of PLA1 was successfully achieved with the aid of a hydrophobic carrier (Accurel MP100) combination with the treatment using glutaraldehyde. The immobilized yield was over 90% based on simple adsorption. The hydrolysis reaction was kinetically investigated through the effect of glutaraldehyde treatment of carrier and water content in the W/O microemulsion phase. The initial reaction rate increased linearly with an increasing glutaraldehyde concentration and then leveled off over a 6% glutaraldehyde concentration. The initial reaction rate, which was predominantly driven by the water content in the organic phase, changed according to a typical bell-shaped curve with respect to the molar ratio of water to phospholipid. It behaved in a similar way with different glutaraldehyde concentrations. After 10 cycles of repeated use, the reactivity was well sustained at 40% of the initial reaction rate and the creation of the final product. Accumulated yield after 10 times repetition was sufficient for industrial applications. Immobilized PLA1 has demonstrated potential as a biocatalyst for the production of phospholipid biochemicals.

Download Full-text

Lipozyme 435-Mediated Synthesis of Xylose Oleate in Methyl Ethyl Ketone

Molecules ◽

10.3390/molecules26113317 ◽

2021 ◽

Vol 26 (11) ◽

pp. 3317

Author(s):

Maria Carolina Pereira Gonçalves ◽

Jéssica Cristina Amaral ◽

Roberto Fernandez-Lafuente ◽

Ruy de Sousa Junior ◽

Paulo Waldir Tardioli

Keyword(s):

Oleic Acid ◽

Methyl Ethyl Ketone ◽

Molar Ratio ◽

Methyl Ethyl ◽

Sugar Ester ◽

Molar Ratios ◽

Emulsion Capacity ◽

Ping Pong ◽

Commercial Sugar ◽

Repeated Use

In this paper, we have performed the Lipozyme 435-catalyzed synthesis of xylose oleate in methyl ethyl ketone (MEK) from xylose and oleic acid. The effects of substrates’ molar ratios, reaction temperature, reaction time on esterification rates, and Lipozyme 435 reuse were studied. Results showed that an excess of oleic acid (xylose: oleic acid molar ratio of 1:5) significantly favored the reaction, yielding 98% of xylose conversion and 31% oleic acid conversion after 24 h-reaction (mainly to xylose mono- and dioleate, as confirmed by mass spectrometry). The highest Lipozyme 435 activities occurred between 55 and 70 °C. The predicted Ping Pong Bi Bi kinetic model fitted very well to the experimental data and there was no evidence of inhibitions in the range assessed. The reaction product was purified and presented an emulsion capacity close to that of a commercial sugar ester detergent. Finally, the repeated use of Lipozyme 435 showed a reduction in the reaction yields (by 48 and 19% in the xylose and oleic acid conversions, respectively), after ten 12 h-cycles.

Download Full-text

Evaluating the effect of repeated use of milling burs on surface roughness and adaptation of digitally fabricated ceramic veneers

Heliyon ◽

10.1016/j.heliyon.2021.e06896 ◽

2021 ◽

Vol 7 (4) ◽

pp. e06896

Author(s):

Leila Payaminia ◽

Naeime Moslemian ◽

Shima Younespour ◽

Soudabeh Koulivand ◽

Marzieh Alikhasi

Keyword(s):

Surface Roughness ◽

Repeated Use

Download Full-text

Critical time for weed removal in glyphosate-resistant soybean as influenced by preemergence herbicides

Weed Technology ◽

10.1017/wet.2019.18 ◽

2019 ◽

Vol 33 (03) ◽

pp. 393-399 ◽

Cited By ~ 5

Author(s):

Stevan Z. Knezevic ◽

Pavle Pavlovic ◽

O. Adewale Osipitan ◽

Ethann R. Barnes ◽

Clint Beiermann ◽

...

Keyword(s):

Field Experiments ◽

Critical Time ◽

Growing Season ◽

Control Programs ◽

Main Plot ◽

Repeated Use ◽

Sites Of Action ◽

Alternative Sites ◽

Preemergence Herbicides ◽

Weed Removal

AbstractWidespread and repeated use of glyphosate resulted in an increase in glyphosate-resistant (GR) weeds. This led to an urgent need for diversification of weed control programs and use of PRE herbicides with alternative sites of action. Field experiments were conducted over a 4-yr period (2015 to 2018) across three locations in Nebraska to evaluate the effects of PRE-applied herbicides on critical time for weed removal (CTWR) in GR soybean. The studies were laid out in a split-plot arrangement with herbicide regime as the main plot and weed removal timing as the subplot. The herbicide regimes used were either no PRE or premix of either sulfentrazone plus imazethapyr (350 + 70 g ai ha−1) or saflufenacil plus imazethapyr plus pyroxasulfone (26 + 70 + 120 g ai ha−1). The weed removal timings were at V1, V3, V6, R2, and R5 soybean stages, with weed-free and weedy season-long checks. Weeds were removed by application of glyphosate (1,400 g ae ha−1) or by hoeing. The results across all years and locations suggested that the use of PRE herbicides delayed CTWR in soybean. In particular, the CTWR without PRE herbicides was determined to be around the V1 to V2 (14 to 21 d after emergence [DAE]) growth stage, depending on the location and weed pressure. The use of PRE-applied herbicides delayed CTWR from about the V4 (28 DAE) stage up to the R5 (66 DAE) stage. These results suggest that the use of PRE herbicides in GR soybean could delay the need for POST application of glyphosate by 2 to 5 wk, thereby reducing the need for multiple applications of glyphosate during the growing season. Additionally, the use of PRE herbicides could provide additional modes of action needed to manage GR weeds in GR soybean.

Download Full-text

Rotation and Continuous use of Dietholate, Fonofos, and SC-0058 on EPTC Persistence in Soil

Weed Science ◽

10.1017/s0043174500056344 ◽

1990 ◽

Vol 38 (2) ◽

pp. 179-185

Author(s):

Brent W. Bean ◽

Fred W. Roeth ◽

Alex R. Martin ◽

Robert G. Wilson

Keyword(s):

Weed Control ◽

Inhibitory Influence ◽

Laboratory Studies ◽

Initial Development ◽

Enhanced Biodegradation ◽

Previously Treated ◽

Repeated Use ◽

Continuous Use ◽

Biodegradation In Soil

Field and laboratory studies were conducted to examine the influence of continuous use and rotation of extenders on EPTC persistence in soils from Clay Center and Scottsbluff, NE. Rotation of EPTC + dietholate and EPTC + fonofos in soils with three prior annual treatments of each combination did not improve weed control compared to continuous use. SC-0058 was generally effective in slowing EPTC biodegradation in soils previously treated with EPTC, EPTC + dietholate, EPTC + fonofos, or EPTC + SC-0058. Dietholate was effective in slowing EPTC biodegradation in soil previously treated with EPTC or EPTC + SC-0058. SC-0058 appeared to have an inhibitory influence on the initial development of soil-enhanced EPTC biodegradation. Any enhanced biodegradation of dietholate or SC-0058 that may occur after repeated use was not a factor in enhanced EPTC degradation in EPTC + extender history soils.

Download Full-text