Complexation of alkyl groups and ghrelin in a deep, water-soluble cavitand

2014 ◽  
Vol 50 (38) ◽  
pp. 4895-4897 ◽  
Author(s):  
Kang-Da Zhang ◽  
Dariush Ajami ◽  
Jesse V. Gavette ◽  
Julius Rebek
Keyword(s):  
Deep Water ◽  
Water Soluble ◽  
Alkyl Groups

A cavitand with ionic, but nonionizable “feet” folds around hydrophobic guests in D2O.

The forage grass Paspalum dilatatum tolerates partial but not complete submergence caused by either deep water or repeated defoliation

2020 ◽  
Vol 71 (2) ◽  
pp. 190
Author(s):  
M. E. Manzur ◽  
A. A. Grimoldi ◽  
G. G. Striker
Keyword(s):  
Deep Water ◽  
Water Soluble ◽  
Plant Performance ◽  
Soluble Carbohydrates ◽  
Shoot Biomass ◽  
Forage Grass ◽  
Submerged Plants ◽  
Paspalum Dilatatum ◽  
Water Columns ◽  
Tiller Angle

Grazing, flooding and their combination are major disturbances that could affect plant performance in humid grasslands. We performed two experiments to study the tolerance of the forage grass Paspalum dilatatum Poir. to different submergence depths and defoliation frequencies. First, we addressed whether this species can shift from the escape strategy to ‘quiescence’ when completely submerged for 30 days. Second, we explored to what extent partial or complete submergence produced by defoliation compromises plant regrowth. The results showed that regardless of the depth of water at submergence, P. dilatatum always responded by attempting to expose its leaf area above water, by increasing the tiller angle and/or blade length (i.e. tiller height). Partially submerged plants showed a reduction in starch concentration (89%) but biomass was unaffected, whereas completely submerged plants did not survive. After one defoliation event, 77% of aerial biomass of partially submerged plants was removed and the concentration of carbon reserves (water-soluble carbohydrates and starch) decreased to half that of control plants. A second event of defoliation (20 days later) of plants with few reserves removed 50–52% of shoot biomass and compromised plant survival, with plants dying before the end of the experiment. In conclusion, P. dilatatum does not tolerate prolonged conditions of complete submergence caused by either deep water columns or repeated defoliation.

scholarly journals Sulfated Alkyl Glucopyranans with Potent Antiviral Activity Synthesized by Ring-Opening Copolymerization of Anhydroglucose and Alkyl Anhydroglucose Monomers

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Shiming Bai ◽  
Davaanyam Budragchaa ◽  
Shuqin Han ◽  
Taisei Kanamoto ◽  
Hideki Nakashima ◽  
...  
Keyword(s):  
Ring Opening ◽  
Model Compound ◽  
Dissociation Rate ◽  
Water Soluble ◽  
Sulfated Polysaccharides ◽  
High Association ◽  
Molecular Weights ◽  
Alkyl Groups ◽  
Dissociation Rate Constants ◽  
Anti Hiv

Sulfated glucopyranans having long alkyl groups were prepared by the ring-opening copolymerization of benzylated 1,6-anhydroglucopyranose with 3-O-octadecyl 1,6-anhydro-β-d-glucopyranose monomers, and subsequent deprotection and sulfation. Water-soluble sulfated glucopyranans with 2.8 and 4.7 mol% of 3-O-octadecyl group and lower molecular weights ofM-n= 2.5 × 103–5.1 × 103have potent anti-HIV activity at 0.05–1.25 μg/mL, even though sulfated polysaccharides with molecular weights belowM-n= 6 × 103had low anti-HIV activity. The interaction with poly-l-lysine as a model compound of proteins was analyzed by SPR, DSL, and zeta potential, indicating that the sulfated 3-O-octadecyl glucopyranans had high association and low dissociation rate constants, and the particle size increased after addition of poly-l-lysine. The anti-HIV activity was induced by electrostatic interaction between sulfate groups and amino groups of poly-l-lysine and by the synergistic effect of the hydrophobic long alkyl chain and hydrophilic sulfated group.

A Deep, Water-Soluble Cavitand Acts as a Phase-Transfer Catalyst for Hydrophobic Species

2006 ◽  
Vol 118 (21) ◽  
pp. 3597-3599 ◽  
Author(s):  
Richard J. Hooley ◽  
Shannon M. Biros ◽  
Julius Rebek
Keyword(s):  
Deep Water ◽  
Phase Transfer ◽  
Water Soluble ◽  
Phase Transfer Catalyst

Rheological Properties of Water Based Drilling Fluid in Deep Water Drilling Conditions

2013 ◽  
Vol 318 ◽  
pp. 507-512 ◽  
Author(s):  
Qian Sheng Yue ◽  
Qing Zhi Yang ◽  
Shu Jie Liu ◽  
Bao Sheng He ◽  
You Lin Hu
Keyword(s):  
Low Temperature ◽  
Rheological Property ◽  
Deep Water ◽  
Viscosity Ratio ◽  
Drilling Fluid ◽  
Wellbore Stability ◽  
Water Soluble ◽  
Water Medium ◽  
Water Based ◽  
Water Base

The rheological property of the drilling fluid was one of the focus problems in deep-water drilling, which was widely concerned. In the article, the viscosity-temperature properties of commonly used water soluble polymeric solution, polymeric brine solution, bentonite slurry, polyacrylamide-potassium chloride drilling fluid with different densities and water-base drilling fluid systems commonly used for China offshore well drillings were studied. 4°C-to-20°C viscosity ratio and 4°C-to-20°C YP ratio were used to judge the thickening level of drilling fluids due to low temperature. The experimental results show that on the condition of without considering the influence of pressure on the rheological property of water-base drilling fluid, its viscosity and yield point raised obviously with the decrease of temperature, but the increase level is proximately the same, its 4°C-to-20°C apparent viscosity ratio is basically within the 1.50. Analysis indicates that the viscosity of water-base drilling fluid depends on the viscosity of dispersed media. The performance of water medium determines the viscosity-temperature property of the water-based drilling fluid. It is proposed that in deep water drillings, if a water-base drilling fluid is used, it is not necessary to emphasize the influence of deep water and low temperature on the flowability. On the condition of guaranteeing wellbore stability and borehole cleaning, it is more suitable for using the water-base drilling fluid with low viscosity and low gel strength for deep water well drillings.

Alkyl Groups Fold to Fit within a Water-Soluble Cavitand

2014 ◽  
Vol 136 (14) ◽  
pp. 5264-5266 ◽  
Author(s):  
Kang-Da Zhang ◽  
Dariush Ajami ◽  
Jesse V. Gavette ◽  
Julius Rebek
Keyword(s):  
Water Soluble ◽  
Alkyl Groups

A Deep, Water-Soluble Cavitand Acts as a Phase-Transfer Catalyst for Hydrophobic Species

2006 ◽  
Vol 45 (21) ◽  
pp. 3517-3519 ◽  
Author(s):  
Richard J. Hooley ◽  
Shannon M. Biros ◽  
Julius Rebek
Keyword(s):  
Deep Water ◽  
Phase Transfer ◽  
Water Soluble ◽  
Phase Transfer Catalyst

scholarly journals Petroleum dynamics in the sea and influence of subsea dispersant injection duringDeepwater Horizon

2017 ◽  
Vol 114 (38) ◽  
pp. 10065-10070 ◽  
Author(s):  
Jonas Gros ◽  
Scott A. Socolofsky ◽  
Anusha L. Dissanayake ◽  
Inok Jun ◽  
Lin Zhao ◽  
...  
Keyword(s):  
Deep Water ◽  
Model Simulation ◽  
Gas Bubbles ◽  
Water Soluble ◽  
Sea Surface ◽  
Chemical Components ◽  
Liquid Droplets ◽  
Buoyant Jet ◽  
Riser Pipe ◽  
Petroleum Fluid

During theDeepwater Horizondisaster, a substantial fraction of the 600,000–900,000 tons of released petroleum liquid and natural gas became entrapped below the sea surface, but the quantity entrapped and the sequestration mechanisms have remained unclear. We modeled the buoyant jet of petroleum liquid droplets, gas bubbles, and entrained seawater, using 279 simulated chemical components, for a representative day (June 8, 2010) of the period after the sunken platform’s riser pipe was pared at the wellhead (June 4–July 15). The model predicts that 27% of the released mass of petroleum fluids dissolved into the sea during ascent from the pared wellhead (1,505 m depth) to the sea surface, thereby matching observed volatile organic compound (VOC) emissions to the atmosphere. Based on combined results from model simulation and water column measurements, 24% of released petroleum fluid mass became channeled into a stable deep-water intrusion at 900- to 1,300-m depth, as aqueously dissolved compounds (∼23%) and suspended petroleum liquid microdroplets (∼0.8%). Dispersant injection at the wellhead decreased the median initial diameters of simulated petroleum liquid droplets and gas bubbles by 3.2-fold and 3.4-fold, respectively, which increased dissolution of ascending petroleum fluids by 25%. Faster dissolution increased the simulated flows of water-soluble compounds into biologically sparse deep water by 55%, while decreasing the flows of several harmful compounds into biologically rich surface water. Dispersant injection also decreased the simulated emissions of VOCs to the atmosphere by 28%, including a 2,000-fold decrease in emissions of benzene, which lowered health risks for response workers.

Normal hydrocarbons tumble rapidly in a deep, water-soluble cavitand

2006 ◽  
pp. 509-510 ◽  
Author(s):  
Richard J. Hooley ◽  
Shannon M. Biros ◽  
Julius Rebek, Jr.
Keyword(s):  
Deep Water ◽  
Water Soluble
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