scholarly journals Synthesis and Polymerization of Macromonomer Having a Phospholipid Polar Group

2000 ◽  
Vol 32 (4) ◽  
pp. 378-380 ◽  
Author(s):  
Tsutomu Oishi ◽  
Hirohito Yamasaki ◽  
Hiromi Kada ◽  
Kenjiro Onimura ◽  
Hiromori Tsutsumi ◽  
...  
Keyword(s):  
Polar Group

Crystal Structure Determination of Glycerol-Containing Lipids from Electron Diffraction Data. Use of Analog Compounds Based upon Configurational Isomers of Cyclopentane-1, 2, 3-TRIOL

1977 ◽  
Vol 35 ◽  
pp. 24-25
Author(s):  
Douglas L. Dorset ◽  
Anthony J. Hancock
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Crystal Surface ◽  
Coherent Scattering ◽  
Crystal Structure Determination ◽  
Electron Diffraction Data ◽  
Polar Group ◽  
Axis Orientation

Lipids containing long polymethylene chains were among the first compounds subjected to electron diffraction structure analysis. It was only recently realized, however, that various distortions of thin lipid microcrystal plates, e.g. bends, polar group and methyl end plane disorders, etc. (1-3), restrict coherent scattering to the methylene subcell alone, particularly if undistorted molecular layers have well-defined end planes. Thus, ab initio crystal structure determination on a given single uncharacterized natural lipid using electron diffraction data can only hope to identify the subcell packing and the chain axis orientation with respect to the crystal surface. In lipids based on glycerol, for example, conformations of long chains and polar groups about the C-C bonds of this moiety still would remain unknown.One possible means of surmounting this difficulty is to investigate structural analogs of the material of interest in conjunction with the natural compound itself. Suitable analogs to the glycerol lipids are compounds based on the three configurational isomers of cyclopentane-1,2,3-triol shown in Fig. 1, in which three rotameric forms of the natural glycerol derivatives are fixed by the ring structure (4-7).

scholarly journals Loss of phosphoserine polar group asymmetry and inhibition of cholesterol transport in Jurkat cells treated with cholesterylphosphoserine

1998 ◽  
Vol 39 (9) ◽  
pp. 1844-1851
Author(s):  
Federico Cusinato ◽  
Walter Habeler ◽  
Francesca Calderazzo ◽  
Francesca Nardi ◽  
Alessandro Bruni
Keyword(s):  
Jurkat Cells ◽  
Cholesterol Transport ◽  
Polar Group

Adsorption of polybutadienes with polar group terminations on the solid surface. 1. Infrared study at the silica surface

1988 ◽  
Vol 21 (4) ◽  
pp. 1059-1062 ◽  
Author(s):  
Masami Kawaguchi ◽  
Minoru Kawarabayashi ◽  
Nobuo Nagata ◽  
Tadaya Kato ◽  
Akira Yoshioka ◽  
...  
Keyword(s):  
Solid Surface ◽  
Silica Surface ◽  
Polar Group ◽  
Infrared Study

Polar‐Group Activated Isospecific Coordination Polymerization of ortho ‐Methoxystyrene: Effects of Central Metals and Ligands

2019 ◽  
Vol 25 (8) ◽  
pp. 2043-2050 ◽  
Author(s):  
Yunjie Chai ◽  
Lingfang Wang ◽  
Dongtao Liu ◽  
Zichuan Wang ◽  
Mingtao Run ◽  
...  
Keyword(s):  
Polar Group ◽  
Coordination Polymerization

Contribution of N2 ion on polar group introduction at PTFE surface by high E/n discharge

2012 ◽  
Vol 179 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Akihiko Nakayama ◽  
Toru Iwao ◽  
Motoshige Yumoto
Keyword(s):  
Polar Group ◽  
Ptfe Surface

scholarly journals Sacrificial amphiphiles: Eco-friendly chemical herders as oil spill mitigation chemicals

2015 ◽  
Vol 1 (5) ◽  
pp. e1400265 ◽  
Author(s):  
Deeksha Gupta ◽  
Bivas Sarker ◽  
Keith Thadikaran ◽  
Vijay John ◽  
Charles Maldarelli ◽  
...  
Keyword(s):  
Crude Oil ◽  
Oil Spill ◽  
Oil Spills ◽  
Cold Water ◽  
Marine Ecosystem ◽  
Hot Water ◽  
Sea Surface ◽  
Marine Biota ◽  
Polar Group ◽  
Branched Chain

Crude oil spills are a major threat to marine biota and the environment. When light crude oil spills on water, it forms a thin layer that is difficult to clean by any methods of oil spill response. Under these circumstances, a special type of amphiphile termed as “chemical herder” is sprayed onto the water surrounding the spilled oil. The amphiphile forms a monomolecular layer on the water surface, reducing the air–sea surface tension and causing the oil slick to retract into a thick mass that can be burnt in situ. The current best-known chemical herders are chemically stable and nonbiodegradable, and hence remain in the marine ecosystem for years. We architect an eco-friendly, sacrificial, and effective green herder derived from the plant-based small-molecule phytol, which is abundant in the marine environment, as an alternative to the current chemical herders. Phytol consists of a regularly branched chain of isoprene units that form the hydrophobe of the amphiphile; the chain is esterified to cationic groups to form the polar group. The ester linkage is proximal to an allyl bond in phytol, which facilitates the hydrolysis of the amphiphile after adsorption to the sea surface into the phytol hydrophobic tail, which along with the unhydrolyzed herder, remains on the surface to maintain herding action, and the cationic group, which dissolves into the water column. Eventual degradation of the phytol tail and dilution of the cation make these sacrificial amphiphiles eco-friendly. The herding behavior of phytol-based amphiphiles is evaluated as a function of time, temperature, and water salinity to examine their versatility under different conditions, ranging from ice-cold water to hot water. The green chemical herder retracted oil slicks by up to ~500, 700, and 2500% at 5°, 20°, and 35°C, respectively, during the first 10 min of the experiment, which is on a par with the current best chemical herders in practice.

scholarly journals Determination of Surfactants in Environmental Samples. Part II. Anionic Compounds

2013 ◽  
Vol 20 (2) ◽  
pp. 331-342 ◽  
Author(s):  
Ewa Olkowska ◽  
Marek Ruman ◽  
Anna Kowalska ◽  
Żaneta Polkowska
Keyword(s):  
Environmental Samples ◽  
Anionic Surfactants ◽  
Solid Phase ◽  
Total Concentration ◽  
Polar Group ◽  
Surface Active Agents ◽  
Assisted Extraction ◽  
Surface Active ◽  
Living Organisms

Abstract Surface active agents (SAA) with negative charge of polar group are named as anionic compounds. They are the main constituent of most products containing synthetic surfactants. The linear alkylbenzene sulfonates (LAS), alkyl ethoxysulfates (AES) and alkyl sulfates (AS) are typically applied from this class of compounds. Those surfactants are ingredients of household detergents and cleaners, laundry detergents, cosmetic etc. Moreover they can be applied in the paper, textile and tanning industry as optical brighteners, dispersant, wetting and suspending agents. They can be substrates in the formulation of different products like dyes, pigments, pesticides, exchange resins, plasticizers and pharmaceuticals. Anionic surfactants after use are passed into sewage-treatment plants, where they are partially degraded and adsorbed to sewage sludge (applied in agriculture fields). Finally, the anionic SAA or their degradation products are discharged into surface waters and onto bottom sediments, soils or living organisms. Therefore, it is important (widely application, bioaccumulation, toxicity for living organisms) to investigate the environmental fate of those class of compounds in more details. This research involves determination the concentration of anionic surfactants with use appropriated analytical techniques in environmental samples The official methodology for determination of anionic SAA in liquid samples is based on the ion-pair reaction of these analytes compounds with methylene blue (MB) and an extraction with toxic solvent chloroform. During isolation step of anionic compounds from solid samples are employed Soxhlet and ultrasonic-assisted extraction techniques with use of methanol or mixture of other organic solvents as extraction medium. To overcome disadvantages of those traditional techniques were applied following techniques at sample preparation step from liquid and solid matrices: solid-phase extraction (SPE) and solid-phases microextraction (SPME); accelerated solvent extraction (ASE), microwave-assisted extraction (MAE), supercritical fluid extraction (SFE), respectively. For estimate total concentration of anionic analytes in extracts the spectrophotometric technique is used (as official regulation). For determination concentration of individual analytes were applied gas (derivatization step requires) and liquid chromatography mainly with mass spectrometry technique. The presence of anionic surface active agents was confirmed in various ecosystems (liquid and solid environmental samples).

Mesomorphic, dielectric, and optical properties of fluorosubstituted biphenyls, terphenyls, and quaterphenyls

2008 ◽  
Vol 16 (4) ◽  
Author(s):  
P. Kula ◽  
A. Spadło ◽  
J. Dziaduszek ◽  
M. Filipowicz ◽  
R. Dąbrowski ◽  
...  
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Dielectric Anisotropy ◽  
Polar Group ◽  
The Novel ◽  
Vertical Alignment ◽  
Rigid Core ◽  
High Birefringence ◽  
Low Viscosity ◽  
Dielectric And Optical Properties

AbstractCompounds with moderate and large negative dielectric anisotropy (Δɛ) are very attractive liquid crystal (LC) for vertical alignment mode (VA). Materials with such properties can be achieved by lateral substitution of a polar group into a mesogenic molecule. We synthesized some new LC materials with a negative value of Δɛ, a moderately high birefringence (Δn), and a low viscosity. The mesomorphic and physical behaviour of the novel biphenyls, terphenyls and quaterphenyls fluorosubstituted in the rigid core and also with fluorinated alkyl and alkoxy chains are investigated. The prepared series of four LC compounds are promising for new LC mixtures for various applications. Examples of nematic mixtures with Δɛ∼−3.25 will be presented.

Olive mill wastewaters: quantitation of the phenolic content and profiling of elenolic acid derivatives using HPLC-DAD and HPLC/MS2 with an embedded polar group stationary phase

2018 ◽  
Vol 33 (21) ◽  
pp. 3171-3175 ◽  
Author(s):  
Marco Mattonai ◽  
Andrea Vinci ◽  
Ilaria Degano ◽  
Erika Ribechini ◽  
Massimiliano Franceschi ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Phenolic Content ◽  
Polar Group ◽  
Olive Mill Wastewaters ◽  
Olive Mill
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